1. A 30-year-old woman sees her physician because she has had diarrhea and
fatigue and has
noticed a 3-kg weight loss over the past 6 months. On physical examination,
she is afebrile and has
mild muscle wasting, but her motor strength is normal. Laboratory studies
show no occult blood,
ova, or parasites in the stool. A biopsy specimen from the upper jejunum is
obtained, and
microscopic findings are reviewed. The patient is placed on a special diet
with no wheat or rye
grain products. The change in diet produces dramatic improvement. Which of
the following
microscopic features is most likely to be seen in the biopsy specimen?
(A)Lymphatic obstruction
(B)Noncaseating granulomas
(C)Villous blunting and flattening
(D)Foamy macrophages within the lamina propria
(E)Crypt abscesses
2. Two days after eating a chicken salad sandwich, a 35-year-old man
experiences cramping
abdominal pain with fever and watery diarrhea. Physical examination shows
mild diffuse
abdominal pain on palpation, but there are no masses. Bowel sounds are
present .A stool sample is
negative for occult blood. He recovers completely within a few days without
therapy. Which of the
following infectious organisms is most likely to produce these findings?
(A)Yersinia enterocolitica
(B)Escherichia coli
(C)Entamoeba histolytica
(D)Salmonella enteritidis
(E)Rotavirus
(F)Staphylococcus aureus
(G)Bacillus cereus
3. A 38-year-old woman has had nausea for the past 6 months. She reports no
vomiting or diarrhea.
On physical examination, there are no remarkable findings. Upper
gastrointestinal endoscopy
shows diffuse gastric mucosal erythema with focal mucosal erosions but no
ulcerations. The
esophageal and duodenal mucosal surfaces appear normal. Microscopic
examination of gastric
biopsy specimens shows increased numbers of neutrophils, lymphocytes, and
plasma cells in the
mucosa, as well as edema, focal mucosal hemorrhage, and loss of the surface
epithelium. No
Helicobacter pylori organisms are seen. Laboratory studies show a normal serum
gastrin level.
Which of the following pharmacologic agents is most likely to produce these
findings?
(A)Acetylsalicylic acid (aspirin)
(B)Acyclovir
(C)Chlorpromazine
(D)Cimetidine
(E)Clindamycin
(F)Omeprazole
(G)Prednisone
4. One year after having an acute myocardial infarction, a 55-year-old man
saw his physician
because of severe abdominal pain and bloody diarrhea. On physical examination,
the abdomen was
diffusely tender, and bowel sounds were absent. Abdominal plain film
radiographs showed no free
air. Laboratory studies showed a normal CBC and normal levels of serum amylase,
lipase, and
bilirubin. His condition deteriorated, and he developed irreversible shock.
At autopsy, which of the
following lesions is most likely to be found?
(A)Acute appendicitis
(B)Acute pancreatitis
(C)Intestinal infarction
(D)Acute cholecystitis
(E)Pseudomembranous colitis
5.A 59-year-old man has had nausea and vomiting for several months. He has
experienced no
hematemesis. On physical examination, there is no abdominal tenderness, and
bowel sounds are
present. Upper gastrointestinal endoscopy shows erythematous areas of mucosa
with thickening of
the rugal folds in the gastric antrum. The microscopic appearance of a gastric
biopsy specimen
with a Steiner silver stain is shown above. Which of the following organisms
is most likely to be
present on the luminal surface?
(A) Salmonella enteritidis
(B) Helicobacter pylori
(C) Staphylococcus aureus
(D) Bacillus cereus
(E) Clostridiun difficile
6.A 62-year-old man sees his physician because he has had fever and back pain
for the past 2 days.
Physical examination shows tenderness of the right costovertebral angle.
Laboratory studies show
leukocytosis and pyuria with WBC casts. He has been receiving antibiotic
therapy with cefotaxime,
clindamycin, and nafcillin for the past l6 days. He now develops lower
abdominal pain and a
severe diarrhea. Clostridium difficile toxin is identified in a stool
specimen. Which of the
following conditions is he most likely to have now developed?
(A)Appendicitis
(B)Collagenous colitis
(C)Diverticulitis
(D)Ischemic colitis
(E)Pseudomembranous colitis
(F)Spontaneous bacterial peritonitis
(G)Typhlitis
7.A 70-year-old man saw his physician for a routine health maintenance
examination. On
physical examination, there were no remarkable findings, but a stool sample
was positive for
occult blood. A colonoscopy was performed and showed a 5-cm sessile mass in
the upper portion
of the descending colon at 50 cm from the anal verge. The histologic
appearance at low power of a
biopsy specimen of the lesion is shown in the figure above. The patient
refused further workup and
treatment. Five years later, he sees his physician because of constipation,
microcytic anemia, and a
5-kg weight loss over the past 6 months. On surgical exploration, there is
a 7 cm mass encircling
the descending colon. Which of the following neoplasms is he now most likely
to have?
(A)Adenocarcinoma
(B)Non-Hodgkin lymphoma
(C)Carcinoid tumor
(D)Leiomyosarcoma
(E)Mucinous cystadenoma
(F)Squamous cell carcinoma
(G)Villous adenoma
8.A 70-year-old man with a lengthy history of chronic alcoholism has had
increasing difficulty
swallowing and has noticed a 6-kg weight loss over the past 2 months. On
physical examination,
there are no remarkable findings. Upper gastrointestinal endoscopy shows a
3-cm ulcerative mass
in the midesophagus that partially occludes the esophageal lumen.
Esophagectomy is performed,
and the gross appearance of the lesion is shown above. Which of the following
is most likely to be
seen on microscopic section of this mass?
(A)Multinucleated cells with intranuclear inclusions
(B)Squamous cell carcinoma
(C)Dense collagenous scar
(D)Adenocarcinoma
(E)Thrombosed vascular channels
9.A 33-year-old man who lives in New York is bothered by a low-volume, mostly
watery diarrhea
associated with flatulence. The symptoms occur episodically, but they have
been persistent for the
past year. He has experienced a 5-kg weight loss. He has no fever, nausea,
vomiting, or abdominal
pain. On physical examination, there are no significant findings. A stool
sample is negative for
occult blood, ova, and parasites, and a stool culture yields no pathogens.
An upper gastrointestinal
endoscopy is performed. A biopsy specimen from the upper part of the small
bowel shows severe
diffuse blunting of villi and a chronic inflammatory infiltrate in the lamina
propria. Which of the
following serologic tests is most likely to be positive in this patient?
(A)Anticentromeric antibody
(B)Anti-DNA topoisomerase I antibody
(C)Antigliadin antibody
(D)Antimitochondrial antibody
(E)Antinuclear antibody
10. A potluck lunch party is held at the office at noon on Thursday.A variety
of meats, salads,
breads, and desserts that were brought in earlier that morning are served.
Everyone has a good time,
and most of the food is consumed. By midafternoon, the single office restroom
is being used by
many employees who have an acute, explosive diarrhea accompanied by abdominal
cramping.
Which of the following infectious agents is most likely responsible for this
turn of events?
(A)Escherichia coli
(B)Staphylococcus aureus
(C)Vibrio parahaemolyticus
(D)Clostridiun difficile
(E)Salmonella enteritidis
(F)Bacillus cereus
11.During summer “Black and white Days,” a week-long local community
celebration of the dairy
industry (Holstein cows are black and white),a 40-year-old man suffers from
episodic abdominal
bloating, flatulence, and explosive diarrhea. On physical examination, there
are no remarkable
findings. Laboratory studies show no increase in stool fat and no occult blood,
ova, or parasites in
the stool. A routine stool culture yields no pathogens. During the rest of
the year, the patient does
not consume milk shakes or ice cream sodas and is not symptomatic. Which of
the following
conditions best accounts for these findings?
(A)Celiac sprue
(B)Autoimmune gastritis
(C)Cholelithiasis
(D)Disaccharidase deficiency
(E)Cystic fibrosis
12. For the past year, a 20-year-old man has had increasingly voluminous,
bulky, foul-smelling
stools and a 10-kg weight loss. There is no history of hematemesis or melena.
He has some
bloating but no abdominal pain. On physical examination, there are no
palpable abdominal masses
and bowel sounds are present. Which of the following laboratory findings is
most likely to be
present on examination of his stool?
(A)Increased stool fat
(B)Giardia lamblia cysts
(C)Occult blood
(D)Vibrio cholerae
(E)Entamoeba histolytica trophozoites
13. A 68-year-old woman has had substernal pain after meals for many years.
For the past year, she
has had increased difficulty swallowing both liquids and solids. On physical
examination, there are
no remarkable findings. Upper gastrointestinal endoscopy shows a lower
esophageal mass that
nearly occludes the lumen of the esophagus. Biopsy of this mass is most likely
to show which of
the following neoplasms?
(A)Adenocarcinoma
(B)Leiomyosarcoma
(C)Squamous cell carcinoma
(D)Non-Hodgkin lymphoma
(E)Carcinoid tumor
14. After an uncomplicated pregnancy, a 23-year-old woman, G 2, P1 gave birth
to a term infant
boy of normal weight and length. The infant initially did well, but at 6 weeks,
he began feeding
poorly for 1 week, and his mother noticed that much of the milk he ingested
was forcefully
vomited within 1 hour. On physical examination, the infant is afebrile, and
there are no external
anomalies. The physician palpates a midabdominal mass. Bowel sounds are
active. The medical
history indicates that the mother and her first child had the same illness
during infancy. Which of
the following conditions is most likely to explain these findings?
(A)Pyloric stenosis
(B)Tracheoesophageal fistula
(C)Diaphragmatic hernia
(D)Duodenal atresia
(E)Annular pancreas
15.A 53-year-old woman has had nausea, vomiting, and midepigastric pain for
5 months. On
physical examination, there are no significant findings. An upper
gastrointestinal radiographic
series shows gastric outlet obstruction. Upper gastrointestinal endoscopy
shows an ulcerated mass
that is 2×4cm at the pylorus. Which of the following neoplasms is most likely
to be seen in a
biopsy specimen of this mass?
(A)Non-Hodgkin lymphoma
(B)Neuroendocrine carcinoma
(C)Squamous cell carcinoma
(D)Adenocarcinoma
(E)Leiomyosarcoma
16.A 60-year-old has had increasing fatigue for the past 8 months. On physical
examination, he
appears pale. On digital rectal examination, no masses are palpable, but a
stool sample is positive
for occult blood. Physical examination of the abdomen shows active bowel
sounds with no masses
or areas of tenderness. Laboratory studies show hemoglobin of 8.3g/dL,
hematocrit 24.6%, MCV
73μm3, platelet count 226,000/mm3 and WBC count 7640/mm3. A colonoscopy shows
no
identifiable source of the bleeding. Angiography shows a l-cm focus of
dilated and tortuous
vascular channels in the mucosa and submucosa of the cecum. Which of the
following is the most
likely diagnosis?
(A)Mesenteric vein thrombosis
(B)Internal hemorrhoids
(C)Angiodysplasia of the colon
(D)Collagenous colitis
(E)Colonic diverticulosis
17. A 43-year-old woman has become increasingly tired and listless over the
past 5 months. She
has had menometrorrhagia for the past 3 months. On physical examination,
there are no
remarkable findings except for a positive result on stool guaiac testing.
Laboratory studies show
hemoglobin of 9.2g/dL, hematocrit 27.3%, and MCV 75μm3. Pelvic ultrasound
reveals an enlarged
uterus. A Pap smear shows abnormal cells of probable endometrial origin.
Colonoscopy is
performed, followed by partial colectomy, with the gross appearance of the
lesion shown in the
preceding figure. Which of the following molecular abnormalities has most
likely led to these
findings?
(A)Mutation in a DNA mismatch repair gene
(B)Germ-line inheritance of an APC gene mutation
(C)Tyrosine kinase activation due to c-KIT mutation
(D)Homozygous loss of the PTEN gene
(E)Inactivation of the Rb protein by HPV-16
18.A 23-year-old woman has had a bloody, mucoid, low-volume diarrhea for the
past 5 weeks. She
has about five stools per day. On physical examination, she is afebrile, and
there is no abdominal
tenderness or masses. Bowel sounds are present. Laboratory studies show no
ova or parasites in the
stool, only mucus and blood with few leukocytes. Colonoscopy shows friable,
erythematous
mucosa extending from the rectum to the middle of the descending colon. A
rectal biopsy
specimen shows acute mucosal inflammation with crypt abscesses and
epithelial cell necrosis.
Which of the following is the most likely diagnosis?
(A)Shigellosis
(B)Ulcerative colitis
(C)Crohn disease
(D)Diverticulitis
(E)Ischemic colitis
19. A-52-year-old man has had a 6-kg weight loss and nausea for the past
6months. He has no
vomiting or diarrhea. On physical examination, there are no remarkable
findings. Upper
gastrointestinal endoscopy shows a 6-cm area of irregular pale fundic mucosa
and loss of the rugal
folds. A biopsy specimen shows a monomorphous infiltrate of lymphoid cells.
Helicobacter pylori
organisms are identified in mucus overlying adjacent mucosa. The patient
receives antibiotic
therapy for H.pylori, and the repeat biopsy shows a resolution of the
infiltrate. Which of the
following is the most likely diagnosis?
(A)Chronic gastritis
(B)Diffuse large B-cell lymphoma
(C)Autoimmune gastritis
(D)Mucosa-associated lymphoid tissue tumor
(E)Crohn disease
(F)Gastrointestinal stromal tumor
20.A 70-year-old man takes large quantities of nonsteroidal
anti-inflammatory drugs (NSAIDs)
because of chronic degenerative arthritis of the hips and knees. Recently,
he has had epigastric pain
with nausea and vomiting and an episode of hematemesis .On physical
examination, there are no
remarkable findings. A gastric biopsy specimen is most likely to show which
of the following
lesions?
(A)Epithelial dysplasia
(B)Hyperplastic polyp
(C)Acute gastritis
(D)Adenocarcinoma
(E)Helicobacter pylori infection
21. A 44-year-old woman has had increasing difficulty swallowing liquids and
solids for the past 6
months. On physical examination, her finger have reduced mobility because
of taut, nondeforming
skin. A barium swallow shows marked dilation of the esophagus with “beaking”
in the distal
portion, where there is marked luminal narrowing. A biopsy specimen from the
lower esophagus
shows prominent submucosal fibrosis with little inflammation. Which of the
following is most
likely to produce these findings?
(A)Portal hypertension
(B)Iron deficiency
(C)Barrett esophagus
(D)CREST syndrome
(E)Hiatal hernia
22.A 35-year-old man has had epigastric pain for over l year. The pain tends
to occur 2 to 3 hours
after a meal and is relieved if he takes antacids or eats more food. He has
noticed a 4-kg weight
gain in the past year. He does not smoke and drinks l glass of Johannisberg
Riesling daily. The
result of a urea breath test is positive, and a gastric biopsy specimen
contains urease. He begins a
2-week course of antibiotics, but on day 4,he feels better and discontinues
treatment. Several
weeks later, the epigastric pain recurs. If the patient does not seek further
treatment, which of the
following complications is he most likely to develop?
(A)Hematemesis
(B)Fat malabsorption
(C)Hepatic metastases
(D)Carcinoid syndrome
(E)Vitamin B12 deficiency
23. A 27-year-old man has sudden onset of marked abdominal pain. On physical
examination, his
abdomen is diffusely tender and distended, and bowel sounds are absent. He
undergoes surgery,
and a 27-cm segment of terminal ileum with a firm, erythematous serosal
surface is removed. The
microscopic appearance of a section through the excised ileum is shown in
the preceding figure.
Which of the following additional complications is the patient most likely
to develop as a result of
this disease process?
(A)Metastatic adenocarcinoma
(B)Mesenteric artery thrombosis
(C)Intussusception
(D)Hepatic abscess
(E)Enterocutaneous fistula
24.An 8-month-old previously healthy infant girl develops a watery diarrhea
that lasts for 1 week.
The infant has a mild fever during the illness but has no abdominal pain or
swelling. On physical
examination, her temperature is 37.7ºC. A stool sample is negative for occult
blood, ova, or
parasites. Her parents are told to give her plenty of fluids, and she recovers
fully. Which of the
fol1owing organisms is most likely to produce these findings?
(A)Campylobacter jejuni
(B)Cryptosporidium parvum
(C)Escherichia coli
(D)Listeria monocytogenes
(E)Norwalk virus
(F)Rotavirus
(G)Shigella flexneri
(H)Vibrio cholerae
25. A 46-year-old woman with a lengthy history of heartburn and dyspepsia
experiences
sudden onset of abdominal pain. On physical examination, she has severe
midepigastric pain with
guarding. Bowel sounds are reduced. An abdominal plain film radiograph shows
free air under the
left leaf of the diaphragm. The patient is immediately taken to surgery, and
a perforated duodenal
ulcer is repaired. Which of the following organisms is most likely to have
produced these findings?
(A)Campylobacter jejuni
(B)Cryptosporidium parvum
(C)Entamoeba histolytica
(D)Giardia lamblia
(E)Helicobacter pylori
(F)Salmonella typhi
(G)Shigella fIexneri
(H)Yersinia enterocolitica
26. A 59-year-old man has had increasing difficulty swallowing during the
past 6 months. There
are no significant findings on physical examination. Upper gastrointestinal
endoscopy shows areas
of erythematous mucosa above the Z-line. A biopsy specimen from the lower
esophagus has the
microscopic appearance shown in the preceding figure. As a consequence of
this patient's
condition, which of the following complications is most likely to occur?
(A)Hematemesis
(B)Squamous cell carcinoma
(C)Adenocarcinoma
(D)Achalasia
(E)Lacerations (Mallow-Weiss syndrome)
27. One day after a meal of raw oysters, a healthy 21-year old woman develops
a profuse, watery
diarrhea. On physical examination, her temperature is 37.5°C. A stool sample
is negative for occult
blood. There is no abdominal distention or tenderness, and bowel sounds are
present. The diarrhea
subsides over the next 3 days. Which of the following organisms is most likely
to produce these
findings?
(A)Yersinia enterocolitica
(B)Staphylococcus aureus
(C)Cryptosporidium parvum
(D)Entamoeba histolytica
(E)Vibrio parahaemolyticus
28. A 57-year-old woman has had burning epigastric pain after meals for more
than 1 year.
Physical examination shows no abnormal findings. Upper gastrointestinal
endoscopy shows an
erythematous patch in the lower esophageal mucosa. A biopsy specimen shows
basal squamous
epithelial hyperplasia, elongation of lamina propria papillae, and scattered
intraepithelial
neutrophils with some eosinophils. Which of the following is the most likely
diagnosis?
(A)Barrett esophagus
(B)Esophageal varices
(C)Reflux esophagitis
(D)Scleroderma
(E)Iron deficiency
29. A 49-year-old woman sees her physician because she has had abdominal
cramps and diarrhea,
with six stools per day for the past month. She has a history of similar
episodes of self-limited pain
and diarrhea, which have occurred several times during the past 20 years.
Each episode lasts about
2 weeks and resolves without treatment. Findings on physical examination are
unremarkable, but a
stool sample is positive for occult blood. Laboratory studies show no ova
or parasites in the stool.
Colonoscopy shows diffuse and uninterrupted mucosal inflammation and
superficial ulceration
extending from the rectum to the ascending colon. Colonic biopsy specimens
from the area show a
diffuse, predominantly mononuclear, infiltrate in the lamina propria. The
patient is at high risk of
developing which of the following complications?
(A)Adenocarcinoma of the colon
(B)Diverticulitis
(C)Primary biliary cirrhosis
(D)Fat malabsorption
(E)Pseudomembranous colitis
(F)Perirectal fistula formation
30. A 4-year-old man has been HIV positive for the past 8 years and has been
receiving highly
active antiretroviral therapy (HAART) for the past year. For the past 2 weeks,
he has experienced
pain when swallowing. He has had no episodes of hematemesis and no nausea
or vomiting. There
are no remarkable findings on physical examination. The CD4+ lymphocyte count
is now 285/μL
Which of the following conditions is most likely to produce these findings?
(A)Esophageal squamous cell carcinoma
(B)Achalasia
(C)Lower esophageal fibrosis with stenosis
(D)Herpes simplex esophagitis
(E)Gastroesophageal reflux disease
31. A 67-year-old woman has experienced severe nausea, vomiting, early
satiety, and a 9-kg weight
loss over the past 4 months. On physical examination, she has mild muscle
wasting. Upper
gastrointestinal endoscopy shows that the entire gastric mucosa is eroded
and has an erythematous,
cobblestone appearance. Upper gastrointestinal radiographs show that the
stomach is small and
shrunken. Which of the following is most likely to be found on histologic
examination of a gastric
biopsy specimen?
(A)Early gastric carcinoma
(B)Gastrointestinal stromal tumor
(C)Granulomatous inflammation
(D)Chronic atrophic gastritis
(E)Signet-ring cell adenocarcinoma
32. A 51-year-old man has sudden onset of massive emesis of bright red blood.
On physical
examination, his temperature is 36.9°C, pulse 103/min, respirations l9/min,
and blood pressure
85/50mm Hg. Laboratory studies show a hematocrit of 21%. The serologic test
result for HBsAg is
positive. He has had no prior episodes of hematemesis. The hematemesis is
most likely to be a
consequence of which of the following?
(A)Esophageal varices
(B)Barrett esophagus
(C)Candida albicans infection
(D)Reflux esophagitis
(E)Squamous cell carcinoma
(F)Zenker diverticulum
33. A 16-year-old boy who is receiving chemotherapy for acute lymphoblastic
leukemia sees the
physician because he has had pain for 1 week when he swallows food. Physical
examination shows
no abnormal findings. Upper gastrointestinal endoscopy shows 0.5- to 0.8-cm
mucosal ulcers in
the region of the middle to lower esophagus. The shallow ulcers are round,
sharply demarcated,
and have an erythematous base. Which of the following is most likely to
produce these findings?
(A)Aphthous ulcerations
(B)Herpes simplex esophagitis
(C)Gastroesophageal reflux disease
(D)Candida esophagitis
(E)Mallory-Weiss syndrome
34. An 11-month-old previously healthy infant has not produced a stool for
l day. The mother
notices that the infant’s abdomen is distended. On physical examination,
the infant's abdomen is
very tender and bowel sounds are nearly absent. An abdominal plain aim
radiograph shows no free
air, but there are distended loops of small bowel with air-fluid levels. Which
of the following is
most likely to produce these findings?
Meckel diverticulum
(B)Duodenal atresia
(C)Hirschsprung disease
(D)Pyloric stenosis
(E)Intussusception
35. A 22-year-old woman has had several episodes of aspiration of food
associated with difficulty
swallowing during the past year. On auscultation, crackles are heard at the
base of the right lung. A
barium swallow shows marked esophageal dilation above the level of the lower
esophageal
sphincter. A biopsy specimen from the lower esophagus shows an absence of
the myenteric ganglia.
Which of the following is the most likely diagnosis?
(A)Hiatal hernia
(B)Plummer-Vinson syndrome
(C)Barrett esophagus
(D)Systemic sclerosis
(E)Achalasia
36. A 53-year-old woman comes to her physician for a routine health
maintenance examination.
The only abnormal finding is a stool specimen that contains occult blood.
Colonoscopy shows a
1.5-cm solitary, rounded, erythematous polyp on a 0.5-cm stalk at the splenic
flexure. The polyp is
removed, and its histologic appearance is shown in the figure below at low
(A) and high (B)
magnifications. When the physician discusses these findings with the patient,
which of the
following statements is most appropriate?
(A)You have inherited one defective copy of the APC gene
(B)Other family members probably have colonic polyps
(C)Many more polyps will appear within the next few years
(D)There is a high probability that you will develop endometrial cancer
(E)A detailed workup to detect metastases from this lesion is not warranted
37. A 20-year-old woman in her ninth month of pregnancy has increasing pain
on defecation and
notices bright red blood on the toilet paper. She has had no previous
gastrointestinal problems.
After she gives birth, the rectal pain subsides, and there is no more bleeding.
Which of the
following is the most likely cause of these findings?
(A)Angiodysplasia
(B)Ischemic colitis
(C)Intussusception
(D)Hemorrhoids
(E)Volvulus
38.A neonate born at 32 week’s gestation was instable condition and feeding
well 3 days after birth.
There was no respiratory distress. On day 4, he infant's abdomen was tender
and appeared
distended. A stool sample is positive for occult blood. Laboratory studies
showed leukocytosis and
a blood culture positive for growth of Esherichia coli. The infant died of
septic shock. Which of
the following is most likely to be found at autopsy?
(A)Dark red necrotic ileum and cecum
(B)Markedly dilated colon above the sigmoid
(C)Purulent ascitic hid
(D)Markedly enlarged mesenteric lymph nodes
(E)A 5-cm mass in the retroperitoneum
39. A 26-year-old man is brought to the emergency department after sustaining
abdominal gunshot
injuries. At laparotomy, while repairing the small intestine, the surgeon
notices a 2-cm mass near
the site of bowel perforation. The yellow tan-colored submucosal ileal mass
is removed. The
electron micrograph of a neoplastic cell from the mass is shown above. Which
of the following is
the most likely cell of origin of this lesion?
(A)Lipoblast
(B)Ganglion cell
(C)Neuroendocrine cel
(D)Smooth muscle cell
(E)Mucin-secreting epithelial cell
40. A 20-year-old woman has had nausea and vague lower abdominal pain for
the past 24 hours,
but now the pain has become more severe. On physical examination, the pain
is worse in the right
lower quadrant, and there is rebound tenderness. A stool sample is negative
for occult blood.
Abdominal plain film radiographs show no free air. The result of a serum
pregnancy test is
negative. Which of the following laboratory findings is most useful to aid
in the diagnosis of this
patient?
(A)Hyperamylasemia
(B)Hypernatremia
(C)Increased serum cacinoembryonic antigen
(D)Increased serum alkaline phosphatase
(E)Leukocytosis
(F)Entamoeba histolytica cysts in the stool
41. Over the past 3 months, a 45-year-old woman has noticed that her skin
has become
progressively more yellow. On physical examination, she is afebrile and has
scleral icterus and
generalized jaundice. Laboratory studies show total serum bilirubin of 8.9
mg/dL, direct bilirubin
6.8 mg/dL, serum ALT l25U/L and AST l08U/L. A liver biopsy specimen shows
histologic features
of sclerosing cholangitis. Which of the following diseases of the
gastrointestinal tract is most likely
to coexist with the liver disease?
(A)Chronic pancreatitis
(B)Diverticulosis
(C)Ulcerative colitis
(D)Celiac sprue
(E)Peptic ulceration
42. One week after a trip to Central America, a 31-year-old woman had an
increasingly severe
diarrhea. Gross examination of the stools showed mucus and streaks of blood.
The diarrheal illness
subsided within a couple of weeks, but now the patient has become febrile
and has pain in the right
upper quadrant of the abdomen. An abdominal ultrasound scan shows a 10-cm
irregular, partly,
cystic mass in the right hepatic lobe. Which of the following infectious
organisms is most likely to
produce these findings?
(A)Giardia lamblia
(B)Cryptosporidiurn porvum
(C)Entamoeba histolytica
(D)Clostridium difficile
(E)Strongyhides stercoralis
43. A 51-year-old woman has been feeling increasingly tired for the past 7
months. There are no
remarkable findings on physical examination. Laboratory studies include
hemoglobin of 9.5g/dL,
hematocrit 29.1%, MCV 124μm3, platelet count 268,000/mm3, and WBC count
8350/mm3. The
reticulocyte index is low. Hypersegmented polymorphonuclear leukocytes are
found on a
peripheral blood smear. Antibodies to which of the following are most likely
to be found in this
patient?
(A)Gliaden
(B)Tropheyma whippelii
(C)Helicobacter pylori
(D)Gastric H+K+-ATPase
(E)Intrinsic factor receptor
44. A 24-year-old woman gives birth to an infant at term after an
uncomplicated pregnancy. Apgar
scores are 9 and 10 at l and 5 minutes after birth. The infant's length and
weight are at the 55th
percentile. There is no significant passage of meconium. Three days after
birth, the infant vomits
all oral feedings. On physical examination, the infant is afebrile, but the
abdomen is distended and
tender and bowel sounds are reduced. An abdominal ultrasound scan shows
marked colonic
dilation above a narrow segment in the sigmoid region. A biopsy specimen from
the narrowed
region shows an absence of ganglion cells in the muscle wall and submucosa.
Which of the
following is most likely to produce these findings?
(A)Hirschsprung disease
(B)Trisomy 21
(C)Volvulus
(D)Colonic atresia
(E)Necrotizing enterocolitis
(F)Intussusception
45. A 24-year-old man sees his physician because of abdominal pain and
increasing fatigue that has
developed over the past 6 months. On physical examination, he is afebrile
and appears pale. On
palpation, there is mild pain in the right lower quadrant of the abdomen.
There are no masses, and
bowel sounds are active. Laboratory studies show hemoglobin of 8.9g/dL,
hematocrit 26.7%,
MCV 74μm3, platelet count 255,000/mm3 and WBC count 7780/mm3. Upper
gastrointestinal
endoscopy and a colonoscopy showed no lesions. One month later, the patient
continues to
experience the same abdominal pain. Which of the following is most likely
to cause this patient's
illness?
(A)Acute appendicitis
(B)Angiodysplasia
(C)Celiac sprue
(D)Diverticulosis
(E)Giardiasis
(F)Meckel diverticulum
46. A 30-year-old man has a routine health maintenance examination. A stool
sample is positive for
occult blood. On colonoscopy, an ulcerative lesion is seen projecting into
the cecum. The
microscopic appearance of a section of the excised lesion is shown in the
figure above. Which of
the following molecular biologic events is thought to be most critical in
the development of such
lesions?
(A)Overexpression of E-cadherin gene
(B)Amplification of ERBB2 gene
(C)Germ-line transmission of a defective RB gene
(D)A defective DNA mismatch-repair gene
(E)Translocation of retinoic acid receptor αgene
47. A l9-year-old man is advised by other family members to see his physician
because genetic
screening has detected a disease in other family members. On physical
examination, a stool sample
is positive for occult blood. A colonoscopy is performed, followed by a
colectomy. The gross
appearance of the mucosal surface of the colectomy specimen is shown above.
Molecular analysis
of this patient's normal fibroblasts is most likely to show a mutation in
which of the following
genes?
(A)APC
(B)p53
(C)K-RAS
(D)HNPCC
(E)NOD2
48. A 38-year-old man who has been HIV positive for l0 years has had severe
nausea and vomiting
for the past 2 weeks. On physical examination, he is afebrile. A stool sample
is positive for occult
blood. The abdomen is not distended, there are no palpable masses or
organomegaly, and bowel
sounds are present. The patient has oral thrush. There are several
reddish-purple, 0.5- to l-cm
nodules on the skin of the trunk. Laboratory studies show a CD4+ lymphocyte
count of l 18/μL.
Upper gastrointestinal endoscopy shows 12 reddish-purple, 0.6 to1.8cm,
gastric mucosal nodules.
A biopsy specimen of the nodules is most likely to show which of the following
neoplasms?
(A)Adenocarcinoma
(B)Non-Hodgkin lymphoma
(C)Carcinoid tumor
(D)Gastrointestinal stromal tumor
(E)Kaposi sarcoma
(F)Peutz-Jeghers polyp
(G)Squamous cell carcinoma
(H)Tubular adenoma
49. A 59-year-old man with a lengthy history of chronic alcoholism has noticed
increasing
abdominal girth for the past 6 months. He has had increasing abdominal pain
for the past 2 days.
On physical examination, his temperature is 38.2°C. Examination of the
abdomen shows a fluid
wave and prominent caput medusae over the skin of the abdomen. There is
diffuse abdominal
tenderness. An abdominal plain film radiograph shows no free air.
Paracentesis yields 500mL of
cloudy yellow fluid. A Gram stain of the fluid shows gram-negative rods. Which
of the following
is the most likely diagnosis?
(A)Appendicitis
(B)Collagenous colitis
(C)Diverticulitis
(D)Ischemic colitis
(E)Pseudomembranous colitis
(F)Spontaneous bacterial peritonitis
50. A 35-year-old woman has had increasing lower back pain for 5 years. At
various times during
the past year, she has also had arthritic pain involving the knees, hips,
and wrists. A stool sample is
positive for occult blood. A pelvic radiograph shows changes consistent with
sacroilitis. A
colonoscopy is performed, and she undergoes a total colectomy. The gross
appearance of the
colectomy specimen is shown in the preceding figure. Which of the following
is the most likely
diagnosis?
(A)Dysregulated CD4+ T-cell responses
(B)Cross-reaction of antibodies against gut bacteria
(C)Autoantibodies directed against tropomyosin
(D)Mutations in the NOD2 gene
(E)Germ-line inheritance of the APC gene mutation
51. A 45-year-old woman is being treated in the hospital for pneumonia
complicated by septicemia.
She has required multiple antibiotics and was intubated and mechanically
ventilated earlier in the
course. On day 20 of hospitalization, she has abdominal distention. Bowel
sounds are absent, and
an abdominal radiograph shows dilated loops of small bowel suggestive of
ileus. She has a low
volume of bloody stool that is positive for Clostridium difficile toxin. At
laparotomy, a portion of
distal ileum and cecum is resected. The gross appearance of the mucosal
surface is shown in the
figure above. Which of the following is the most likely diagnosis?
(A)Mesenteric arterial thrombosis
(B)Pseudomembranous enterocolitis
(C)Intussusception
(D)Cecal volvulus
(E)Toxic megacolon
52. A 52-year-old previously healthy man sustained an extensive thermal burn
injury involving
70% of the total body surface area of his skin. He was hospitalized in stable
condition. Three
weeks after the initial burn injury, he had melanotic stools. His blood
pressure was 80/40mm Hg,
and his hematocrit was l8%. Soon after, he experienced cardiac arrest and
could not be resuscitated.
At autopsy which of the following is most likely to be found?
(A)Multiple 2 to 5-mm ulcers throughout the gastric mucosa that penetrate
the submucosa
and the muscularis propria
(B)Prominent and tortuous veins at the gastroesophageal junction with
overlying irregular
0.5- to l-cm ulcerations penetrating to submucosa
(C)A single l-cm punched-out ulcer in the gastric antrum that penetrates the
submucosa and
has a base alied with granulation tissue
(D)Multiple 2 to 5 mm ulcers throughout the gastric mucosa that are confined
to the mucosa
(E)Multiple 2 to 5 mm ulcers in metaplastic columnar epithelium at the lower
end of the
esophagus
53. A 68-year-old woman with a history of rheumatic heart disease is
hospitalized with severe
congestive heart failure. Several days after admission, she develops
abdominal distention. On
physical examination, she is afebrile. The abdomen is tympanitic, without
a fluid wave, and bowel
sounds are absent. A stool sample is positive for occult blood. An abdominal
plain film radiograph
shows no free air. Colonoscopy shows patchy areas of mucosal erythema with
some overlying tan
exudate in the ascending and descending colon. No polyps or masses are found.
Which of the
following is the most likely diagnosis?
(A)Ulcerative colitis
(B)Volvulus
(C)Shigellosis
(D)Mesenteric vasculitis
(E)Ischemic colitis
54. A 27-year-old man has had intermittent cramping abdominal pain and
low-volume diarrhea for
several weeks. On physical examination, he is afebrile; there is mild lower
abdominal tenderness
but no masses, and bowel sounds are present. A stool sample is positive for
occult blood. The
symptoms subside within l week. Six months later, the abdominal pain recurs
with perianal pain.
On physical examination, there is now a perirectal fistula. Colonoscopy shows
many areas of
mucosal edema and ulceration and some areas that appear normal. Microscopic
examination of a
biopsy specimen from an ulcerated area shows a patchy acute and chronic
inflammatory infiltrate,
crypt abscesses, and several noncaseating granulomas. Which of the following
underlying disease
processes best explains these findings?
(A)Crohn disease
(B)Amebiasis
(C)Shigellosis
(D)Sarcoidosis
(E)Ulcerative colitis
55. A 49-year-old man has complained of “heartburn” after meals for the
past decade. There are
no remarkable findings on physical examination. Upper gastrointestinal
endoscopy is performed,
and an esophageal biopsy specimen is taken from an erythematous area of
velvety mucosa just
above the gastroesophageal junction. Microscopically, the mucosa shows
columnar metaplasia
with goblet cells. Which of the following most likely produced these
findings?
(A)Esophageal varices
(B)Radiation therapy
(C)Achalasia
(D)Gastroesophageal reflux disease
(E)Iron deficiency anemia
56. A 65-year-old woman goes to her physician for a routine health maintenance
examination. A
stool sample is positive for occult blood. CT scan of the abdomen shows
numerous air-filled, l-cm
outpouchings of the sigmoid and descending colon. Which of the following
complications is most
likely to develop in this patient?
(A)Adenocarcinoma
(B)Pericolic abscess
(C)Bowel obstruction
(D)Malabsorption
(E)Toxic megacolon
57. A 45-year-old woman has had increasing abdominal distention for the past
6 weeks. On
physical examination, there is an abdominal fluid wave and bowel sounds are
present. Paracentesis
yields 1000mL of slightly cloudy serous fluid. Cytologic examination of the
fluid shows malignant
cell consistent with adenocarcinoma. The patient’s medical history
indicates that she has had no
major medical illnesses and no surgical procedures. Which of the following
conditions is most
likely to have preceded the development of the adenocarcinoma?
(A)Angiodysplasia
(B)Crohn disease
(C)Diverticulosis
(D)Hereditary nonpolyposis colon carcinoma
(E)Hirschsprung disease
(F)Peptic ulcer disease
58.A 32-year-old man sees the physician because he has experienced nausea
and vomiting for the
past week. On physical examination, he appears cachectic and says that he
has noticed a 15-kg
weight loss over the past 2 months. A 10-cm nontender mass is palpable in
the midabdominal
region. An abdominal CT scan shows that the mass involves the small intestine.
Serologic tests
indicate that he is HIV positive. A biopsy specimen is most likely to show
which of the following
microscopic features?
(A)Blunting and flattening of villi containing increased numbers of
lymphocytes and plasma
cells (B)Densely packed tubular glands lined by dysplastic cells with
hyperchromatic nuclei
(C)infltrates of large monoclonal B lymphocytes
(D)Irregular ulceration with chronic inflammation and granuloma formation
(E)Sharply demarcated ulceration with epithelial cells containing
intranuclear inclusions
59. In an epidemiologic study of infection of the gastrointestinal tract,
cases of patients from whom
definitive cultures were obtained are analyzed for clinical and pathologic
findings that may be
useful for diagnosis. A subset of patients is identified who initially had
abdominal pain and
diarrhea during week 1 of their illness. By week 2, these patients had
splenomegaly and elevations
in serum AST and ALT levels. By week 3, they were septic and had leukopenia.
At autopsy, those
who died were found to have ulceration of Peyer's patches. Which of the
following infectious
agents is most likely to produce these findings?
(A)Campylobacterl jejuni
(B)Clostridium perfringens
(C)Ehcherichia coli
(D)Mycobacterium bovis
(E)Salmonella typhi
(F)Shiglla sonnei
(G)Yersinia enterocolitica
60. A 57-year-old man goes to the emergency department because of increasing
abdominal pain
with distention that developed over the past 24 hours. On physical
examination, there is diffuse
abdominal tenderness. The abdomen is tympanitic, without a fluid wave, and
bowel sounds are
nearly absent. There is a well-healed, 5-cm transverse scar in the right lower
quadrant of the
abdomen. There is no caput medusae. A stool sample is negative for occult
blood. An abdominal
plain film radiograph shows dilated loops of small bowel with air-fluid
levels, but there is no free
air. At laparotomy, the surgeon notices a 20-cm portion of reddish-black
ileum that changes
abruptly to pink-appearing bowel on both distal and proximal margins. The
patient's medical
history is signiacant only for an appendectomy at age 25. Which of the
following is most likely to
have produced these findings?
(A)Adenocarcinoma of the ileum
(B)Adhesions
(C)Angiodysplasia
(D)Crohn disease
(E)Indirect inguinal hernia
(F)Intussusception
(G)Volvulus