Case: E25436-98: 21 year old horse.
Describe the lesion: A pedunculated, firm, globoid mass approximately 2cm in
greatest diameter that is attached to the serosal surface of the colon.
Morphologic diagnosis: Benign tumor
Differentials: Leiomyoma (what it is), gastrointestinal stromal tumor, lipoma (if
from the mesentery and not the serosa), metastatic neoplasia, lymphoma
Case: C5652-03: Six year old, male castrated, malamute with a history of large
bowel diarrhea, tenesmus, mucous and frank blood in the stool.
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Describe the lesion: A large, round, 10cm in greatest diameter, soft mass infiltrates
the intestinal wall and expands the surrounding connective tissue. On cut surface,
the tumor is tan, homogeneous with small foci of hemorrhage.
Give differentials: Lymphosarcoma (what it is), visceral mast cell tumor,
Leiomyosarcoma, fibrosarcoma, gastrointestinal stromal tumor, adenocarcinoma,
metastatic, malignant neoplasia.
Case: E6072-06: Adult horse who presented due to colic.
Describe the lesion: Solid, firm, tan-red irregular mass expands the wall of the
intestine
Give differentials: Gastrointestinal stromal tumor (what this is), leiomyosarcoma,
fibrosarcoma, lymphosarcoma
GIST in a dog
Case: E3176-95: 20 year old Shetland Bay Pony
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Morphologic diagnosis: Mesenteric (pedunculated) lipoma
This pony was euthanized because of laminitis and this was an incidental finding in
this case, occasionally pedunculated lipomas can entrap bowel (called strangulating
lipoma,),which results in infarction of bowel and colic.
Case F16899-94: Eight year old, female spayed domestic short hair cat.
Describe the lesion: Multiple small masses are present within the mesentery. The
distal colon has a large 2-3cm long, pale, friable, mass encircling it and occluding the
lumen.
Give differentials: Adenocarcinoma (with carcinomatosis), carcinoid, metastatic
neoplasia
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Case C24336-03 Twelve year old, female spayed Labrador retriever.
Describe the lesion: The intestine is thickened by a transmural, poorly demarcated
white, firm mass.
Most likely diagnosis: This is intestinal lymphosarcoma, but histology is required
for diagnosis.
Case F10393-99: 15 year old, female spayed domestic short hair cat.
Describe the lesion: Multiple, nonencapsulated, multilobular, firm masses occupy
segments of the wall of the intestine. The masses penetrate the mucosa and cause
ulceration. Most likely diagnosis: Alimentary lymphoma (associated with FeLV),
would need histology to confirm.
Case: P22291-99 153 day old pig from the finishing barn.
Describe the lesion: The ileum is thickened with a marked corrugated appearance
and evidence of necrosis and friable material (fibrin), present on the surface.
Give a morphologic diagnosis: Ileum: chronic, diffuse/segmental/locally
extensive, proliferative, fibrinonecrotizing ileitis (enteritis)
Etiology: Lawsonia intracellularis so-called “proliferative enteropathy”
Case: O7937-09 2 months old, female lamb with progressive weight loss and
hypoproteinemia.
Describe the lesion: The small intestine is thickened and covered by multiple,
raised, white to tan nodular masses.
Give a morphologic diagnosis: intestine: chronic, marked, segmental, proliferative
ileitis with lymphoid hyperplasia (peyer’s patches)
Differentials: Terminal or regional ileitis in 1-4 month old lambs is a non-specific
disease thought to be related to Border disease virus infection, coccidiosis would be
a differential
Coccidiosis in sheep (hyperplasia of Peyer’s patches)
Case: F16184-07 2 month old, male kitten
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Describe the changes: The serosal surface of the intestine is dark red and
edematous. The intestine is thickened and has friable material on the mucosal
surface.
Give a morphologic diagnosis: intestine: enteritis, fibrinonecrotizing, segmental to
locally extensive, severe, subacute
Etiology? Feline panleukopenia (parvovirus)
This disease is most often seen in young, unvaccinated animals and in conditions
where a large number of cats coinhabitate such as shelters and feral environments.
Case: C16208-98 Three month old, female chocolate lab.
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Describe the lesion: The serosal surface has a ground glass appearance. The wall is
thickened and the mucosal surface is covered by brown flaky material and blood.
Morphologic diagnosis: Small intestine: necrotic and hemorrhagic enterocolitis,
segmental and severe
Likely etiology: canine parvovirus 2
Case: G19601-95 Six month old, Angora goat kid.
Describe the lesion: Numerous, slightly raised, multifocal to coalescing small
white foci (approximately 1mm in diameter) are scattered throughout the mucosal
of the jejunum and ileum, occasionally extending to the serosal surface.
Morphologic diagnosis: small intestine: chronic, proliferative enteritis
Etiology: coccidiosis
The presence of coccidian life stages (usually Eimeria sp.) within the cytoplasm of
enterocytes causes proliferation of the intestinal glands, resulting in the gross
appearance.
A2544-90. Duck found dead.
Describe the lesion: Numerous, 2-5mm, firm, white nodules are present on the
visceral and parietal peritoneum. On cut surface, the nodules have an inner brown,
casseous core and an outer rim of white tissue.
Give a morphologic diagnosis: intestine: chronic, moderate-severe,
granulomatous, enteritis
What is the most likely etiology? Avian tuberculosis (Mycobacterium avium)
Case: E745-07: 23 year old, female pony with a history of colic.
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Describe the lesion: The serosa is expanded by many multifocal to coalescing, redyellow (pink at this point) plaques (1-3mm by 5-15mm)
What is the cause of this lesion? This is hemomelasma ilei due to migration of
Strongylus sp. (usually S. edentatus) and is considered an incidental finding. This
pony had symptoms of colic because of a pedunculated lipoma and torsion of the
small intestine.
Case: E25958-11. Hanovarian foal with signs of abdominal pain (pawing, backing up
and lying down).
Describe the lesion: Fibrinous exudates admixed with digesta covers the serosal surfaces
primarily of the proximal to mid jejunum. A small (approximately 5mm) transmural rent
with red margins is present within the wall of the proximal to mid-jejunum.
Morphologic diagnosis: Jejunal perforation and fibrinous peritonitis
Large numbers of ascarids were present within the small and large intestines (Parascaris
equorum) and may be associated with the rupture.
Case: X6240-12: Male leopard gecko
Describe the lesion: The descending colon and rectum are diffusely markedly dilated with
intraluminal accumulation of ingesta and thinning of the intestinal wall (megacolon). A
small (approximately 1mm) transmural tear in the rectal wall is present (rectal
perforation).
Morphologic diagnosis: Megacolon with peracute rectal perforation
This is a relatively common finding in geckos and is often due to ingestion of fine substrate
in the enclosure (pica).
Case A16909-96. Three month old turkey found dead.
Describe the lesion: Both ceca are bilaterally distended. The mucosa has a dull,
granular appearance with abundant, friable, easily peeled fibrin at the surface.
Morphologic Diagnosis: Ceca: Bilateral, severe, fibrinonecrotizing typhlitis
Etiology: This is a typical lesion of infection with Histomonas gallinarum a protozoal
parasite that also causes multifocal hepatic necrosis. The protozoa is carried by the
nematode Heterakis meleagridis.
Case: B240-97: Four year old Chianina/Angus cross cow
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Describe the lesion: Peyer’s patches are dark red and frequently contain
fibrinonecrotic material attached to the surface
Morphologic diagnosis: Ileum: Peyer’s patch necrosis, fibrinonecrotic, focal
enteritis
What is the likely etiology?
This lesion is characteristic of Bovine Viral Diarrhea (pestivirus) mucosal disease
when a persistently infected animal is exposed to a cytopathic form of the virus.
Case X3152-12 Boa constrictor: History of inappetance (for three months) and
regurgitation.
Describe the lesion: The serosal surface of the proximal small intestine is granular
to roughened and red with adhesions to the surrounding tissues. There is marked
thickening of the wall at this site and a thick layer of fetid yellow friable material is
adhered to the mucosal surface.
Morphologic diagnosis: small intestine: subacute, severe, segmental
fibrinonecrotizing enteritis
Differentials: Salmonella sp., Entamoeba sp. and secondary bacterial infection due
to immunosuppression from Inclusion Body Disease (this case)
Case X27578-09 Nine year, female, Alpaca
Describe the lesion: The wall of the intestine is thickened. The mucosal surface is
irregularly friable with multifocal areas of mucosal depression and reddening with
superficial adherence of fibrin.
Give a morphologic diagnosis: small intestine: segmental, fibrinonecrotizing
enteritis
Give differentials: Salmonella sp., coccidiosis (Eimeria sp.), bovine viral diarrhea
http://nematode.net
Pig with Ascaris suum.
Case: P2211-96 Male, castrated, weaner pig. (also P26609-11)
Button ulcers in a pig due to Classical Swine Fever (quizlet.com)
Describe the lesion: The cecum and large intestine have numerous, 0.2-1cm,
raised, white areas on the mucosal surface, with central depressions.
Morphologic diagnosis: colon and cecum: subacute, severe, multifocal, necrotizing
typhlocolitis with ulcerations (P26609-11 is more fibrinonecrotizing typhlocolitis)
Differentials: Salmonella!!!!!! (button ulcers are characteristic of Salmonella and
hog cholera, Brachyspira sp. can cause ulcerative typhlocolitis)
Name a common sequela rectal stricture (from ischemic injury)
Case: C18332-05: Two year old female spayed German Shepherd with a history of
vomiting and diarrhea.
Describe the lesion: The cecum and colon have a thickened wall and mesenteric
lymph nodes were enlarged.
Morphologic diagnosis: Locally extensive granulomatous (histology) enteritis and
mesenteric lymphadenitis.
Possibly related to Mycobacterium avium sp. There is a histiocytic colitis condition
described in boxers (histologic diagnosis).
inBoxers (http://studydroid.com)
Case: P23171-97 Fetus
Give a morphologic diagnosis: schistosomas reflexus
Histiocytic and ulcerative colitis
Case: C10954-08: Three year old, Shetland Sheepdog.
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Describe the changes: The intestinal lymphatics are distended and several, white, firm,
gritty plaques and nodules are present on the serosa of the small intestine on the
mesenteric border.
Think of a morphologic diagnosis: Lymphangectasia and lymphangitis (histologic
diagnosis is lipogranulomatous lymphangitis with mild, lymphplasmacytic enteritis).This
dog also had chylothorax and chyloabdomen presumably resulting from rupture of the
lymphatics in response to ongoing inflammation. Dogs with this condition usually have a
protein losing enteropathy with clinical signs of diarrhea, steatorrhea, hypoproteinemia,
hydrothorax, ascites and peripheral edema. The condition is considered an inherited
disease especially in small breed dogs (yorkies) with the chronic inflammation developing
in response to leakage from lymphatics.
Case C12076-89 Seven year old, mixed breed dog. Had puppies six months ago.
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Describe the lesion: A 5-6cm piece of rectum is markedly congested and edematous and
has invaginated upon itself
Morphologic diagnosis: rectal prolapse
This lesion is associated with abdominal straining such as from pregnancy, parturition, and
diarrhea. It is also common in feedlot heifers (especially Herefords) for genetic and
presumably dietary reasons. In exotic species it has been associated with hypocalcemia and
vitamin D deficiencies.
Case: E3041-87: Six week old, male foal (and B1214-96) and B11650-04)
Describe the lesion: A large section of bowel is telescoped upon itself, the segments are
firmly attached to one another and the entrapped segment is dark red and necrotic
(infarcted)
Morphologic diagnosis: Acute, severe, focal intussusception
Animals die from this condition due to compromise of bowel and release of bacteria and
their toxins into the bloodstream resulting in a cytokine response that causes shock and
death. Inflammatory conditions causing enteritis (such as previous viral, bacterial or
parasitic infection) have been associated with this condition.