the hematopoietic and
lymphoid systems
hematopathology
• blood
• lymphoid organs
– central:
• bone marrow
• thymus
– peripheral:
• lymph nodes
• MALT (Waldeyer´s ring,
intestine...)
• splenic white pulp
hematopathology
• leukaemia = neoplastic cells in peripheral
blood
• lymphoma = tumour of the lymph node
• hemoblastosis
– primary bone marrow
– leukaemia + tumoriform
• lymphomas
– primary lymph nodes
– lymphoma + leukemic phase
bone marrow
bone marrow
• weight cca 1,5kg
• red (hematopoietic) x yellow (adipose)
• structure:
– hematopoietic cells: granulopoiesis
peritrabecular, erytropoiesis a
megakaryocytes intertrabecular and
perisinusoidal
– corroborative elements: makrophages,
fibroblasts, mastocytes, plazmocytes,
lymfocytes
– blood sinuses
– bone trabeculas
diminished hematopoiesis
A) total diminution
aplastic anemia (panmyelophtisis)
• hereditary:
– Fanconi anemia
• AR
• death because of infectious and bleeding
complications
• +/- turn into AML
• acquired:
– infectious, irradiation, use of some drugs
diminished hematopoiesis
B) selective
• one or more of hematopoietic lineages
critical is peripheral blood – marrow could
be hypercelular = „ineffective
hematopoiesis“
diminished
hematopoiesis...anemia
1) anemia
• ↓ total circulating RBC volume, +/- ↓Hb
and ↓O2
• hypoxia of tissues = clinical symptoms
anemia...loss of RBC
a) hemorrhage: blood loss anemia
• hypovolemia → normocytic
normochromic anemia → ↑ erytropoiesis
(bone marrow) → reticulocytosis,
hypochromic anemia
anemia...hemolytic
b) increased rate of RBC destruction: the
hemolytic anemias
• anemia + reactive hyperplastic
erytropoiesis
• bm: ↑erytropoiesis/myelopoiesis,
gaucheroid cells
• +/- extramedullary hematopoiesis
• Hb -emia, -uria
anemias..hemolytic..intrinsic
I) intrinsic (intracorpuscular)
abnormalities of RBC
 hereditary:
 1) disorders of RBC membrane cytoskeleton
spherocytosis
– erythrocytes spheroidal, less deformable and
vulnerable to splenic sequestration and
destruction
– AD
– anemia, splenomegalia a hemolytic icterus
anemias..hemolytic..intrinsic
RBC enzyme deficiencies
3) disorders of Hb synthesis: hem+globin
deficient globin synthesis: thalassemia
syndromes
2)
– lack of or decreased synthesis of globin chains:
α chains = α thalassemia
β chains = β thalassemia
– ↓ synthesis of Hb → anemia (microcytic hypochromic)
+ excess of α chains in β thalassemia → insoluble
aggregats → damage RBC membrane → reduction of
plasticity → phagocytosis, inefective erytropoiesis
– heterozygous = thalassemia minor
homozygous = thalassemia major
anemias..hemolytic..intrinsic
structurally abnormal globin synthesis
(hemoglobinopathies): sickle cell anemia
– structurally abnormal Hb S – on
deoxygenation polymerization = gelation or
crystallization → microvascular obstruction
→ ischemic tissue damage + ↑ removing in
the spleen = „autosplenectomy“
anemias..hemolytic..intrinsic
 acquired
membrane defect: paroxysmal nocturnal
hemoglobinuria)
– ↓resistance against C3
– granulocytes and plateles affected too →
hemolysis, +/- trombotic complications and
↑ susceptibility to infections
anemias..hemolytic..extrinsic
II) extrinsic (extracorpuscular)
abnormalities
1) antibody mediated
 isohemagglutinins
erythroblastosis fetalis
– Rh (mother Rh-, father and child Rh+)
– antibodies against fetal RBC
– hydrops fetus universalis, mental retardation,
↑extramedulary hematopoiesis
anemias..hemolytic..extrinsic
 autoantibodies
– idiopathic (primary), drug associated, SLE
– Coombs tests
anemias..hemolytic..extrinsic
mechanical trauma to RBCs
 mikroangiopathic hemolytic anemias
2)
– DIC, TTP
 mechanic traumatization of
erythrocytes
– dialysis, valves prosthesis
3)
infections (malaria)
anemia...impaired RBC production
c) diminished erythropoiesis
1) combination with the others in aplastic
anemia
2) pure „erytroblastophtisis“
Blackfan-Diamond syndrom
• children
• + thymomas and T-CLL
3) myelophtisic anemia
• extensive replacement of the marrow by
tumours or other lesions → extramedullary
hematopoiesis, leukoerythroblastosis
anemia...impaired RBC production
iron deficiency anemia
most common
mikrocytar hypochromic
↓low intake (diets, malabsorptions) x
↑ demands (pregnancy, infancy, chronic
blood loss)
gross: hypoxic myocardial steatosis
marrow normal or hyperplastic
erythropoiesis, decline in serrum ferritin
and depletion of stainable iron in the bone
marrow
4)
•
•
•
•
•
anemia...impaired RBC production
megaloblastic anemia
disturbance of proliferation and
differentiation of erythroblasts →
megaloblasts, megakaryocytes
nuclear-cytoplasmic asynchrony
giant metamyelocytes → hypersegmented
neutrophils
ineffektive erythropoiesis
folate (folic acid) deficiency anemia
tetrahydrofolate
neurologic abnormalities do not occur
5)
•
•
•
•

•
•
anemia...impaired RBC production
 pernicious anemia
• vitamin B12 (cobalamin) deficiency
• diet, ↓intrinsic faktor (parietal gastric
cells), terminal ileum
• gross: atrophic glossitis, gastritis,
demyelinization
anemia...impaired RBC production
lack of erythropoietin
• kidney failure, parvovirosis (B19)
6)
diminished hematopoiesis...
leukopenia
2) leukopenia
a) lymfopenia
• hereditary immunity disorders,
infections(viral), chronical diseases,
steroid therapy
leukopenia
b) neutropenia (granulocytopenia)
• increased susceptibility to infections
• marrow failure (aplastic anemia) →
agranulocytosis
• inadequate or ineffective granulopoiesis: certain
drugs: benzen, purin and pyrimidin analogs,
anthracyklin x idiosyncrastic reaction
(chloramfenikol, chlorpromazin, fenylbutazon)
• accelerated removal or destruction of
neutrophils: hypersplenism, certain drugs
• bm: depend on the underlying basis: ↑ or ↓
granulopoiesis and +/- reaction to infection
increased hematopoiesis
• transitory increasing of hematopoiesis
1) ↑erythropoiesis = polycythemia
• increased erythropoietin levels:
– appropriate: lung disease, high-altitude living,
cyanotic heart disease
– inappropriate: erythropoietin-secreting
tumours, „doping“
• bm hypercellular, inappropriate increasing
of erythropoiesis
• no extramedullary hematopoiesis!
increased hematopoiesis
2) leukocytosis
a) lymfocytosis: chronical infections (IM)
b) granulocytosis: acute bacterial infections
(pyogenic organisms), sterile inflammation
(tissue necrosis, burns) → leukemoid
reaction (like in CML)
c) eosinophilia: allergic disorders, parasitic
infestation, drug reaction, certain mlg
3) thrombocytosis: infections, chronical
bleeding, tumours, iron deficiency
myelodysplastic syndromes
• heterogeneous group of disorders
• some evidence of bone marrow failure and
dysplasia in one or more myeloid cell
lineages
• may evolve to AML
• chromosomal aberrations
• primary x secondary (radiotherapy,
alkylating agent therapy)
• bm hypercellular, ↑ erythropoiesis,
morphological changes, +/- fibrosis
myelodysplastic
syndromes...histological
classification
 refractory anemia (RA)
 refractory anemia with ring sideroblasts
(RARS)
 refractory cytopenia with multilineage
dysplasia
 refractory anemia with excess blasts
(RAEB)
 MDS, unclassifiable
chronic myeloproliferative diseases
• CMPDs: clonal haematopoietic stem cell
disorders characterised by proliferation
in the bone marrow of one or more of the
myeloid (i.e. granulocytic, erythroid and
megakaryocytic) lineages
CMPD
A) chronic myelogenous leukaemia
• most common
• adults, 30-60eyars
• neutrophilic leukocytosis in peripheral
blood
• Ph+ = t(9;22) = Philadelphia chr.
• bm: hypercellular (↑granulopoiesis,
↑megakaryocytes), +/- fibrosis
• extramedullary leukaemic infiltration:
spleen, liver
• → accelerated phase → blast phase
CMPD
B) polycythaemia vera (polycythaemia
rubra vera, m. Vaquez-Osler)
• ↑ erythropoiesis
• hypertension, thrombosis, haemorrhage
• bm:
– initial phase: hypercellular, with increased
erythropoiesis + extramedullar infiltration →
hepatosplenomegaly
– +/- blast phase or „spent“ phase
CMPD
C) essential thrombocythaemia
• proliferation primarly magakaryocytic
lineage
• sustained thrombocytosis in the blood
• bm: large, mature megakaryocytes
D) chronic idiopathic myelofibrosis
• proliferation of mainly megakaryocytes,
associated with reactive deposition of
bone marrow connective tissue and
extramedullary hematopoiesis
acute leukaemias
• causes:
– complication of certain chromosomal diseases (m.
Down, Fanconi anemia, Klinefelter´s syndroma...)
– radiation
– chemicals (benzen, alkylating agents, drugs)
– viruses (HTLV-1)
• AML, ALL
• symptoms: combination of aplastic anemia and
agranulocytosis
• bm: leukaemic infiltration, +/- extramedullar
infiltration (liver, spleen, kidney, CNS)
• myelosarcoma („chloroma“)
acute myeloid leukaemias...
histological classification
 M0...acute myeloblastic l. minimally
differentiated
 M1...acute myeloblastic l. without
maturation
 M2...acute myeloblastic l. with maturation
 M3...acute promyelocytic l.
 M4...acute myelomonocytic l.
 M5...acute monocytic l.
 M6...acute erythroid l.
 M7...acute megakaryoblastic l.
acute lymphoblastic leukaemias...
histological classification
 precursor B- and T- cell lymphoblastic
leukaemia/lymphoblastic lymphoma
proliferation of macrophages,
histiocytosis
A) reactive proliferation of macrophages
• bone marrow, many causes (hemosiderosis,
aiha, viral infections)
• lysosomal storage diseases (m. Gaucher,
Niemann-Pick...)
proliferation of macrophages,
histiocytosis
B) hemofagocytic syndroma
• ↑ proliferation of macrophages or
histiocytic precursores →
haemofagocytosis → cytopenia
• + hepatosplenomegaly, fever
• proliferating macrophages: clonal (mlg
histiocytosis) x reaction (infection,
Kawasaki, T lymphomas)
• fatal haemofagocytosis
proliferation of macrophages,
histiocytosis
C) histiocytosis X (Langerhans cells
histiocytosis)
1) solitary eosinophilic granuloma
– bng
– bones (unifocal lytic lesion), skin, lymph nodes,
lungs
– Langerhans cells (Birbeck granules) +
eosinophils, +/- plasma cells and lymphocytes
2) m. Hand-Schüler-Christian
– trias: multifocal lytic lesions of bone +
exophtalamus + diabetes insipidus
proliferation of macrophages,
histiocytosis
3) m. Abt-Letterer-Siwe
– mlg
– children before 2 years of age
– cutaneous lesions resembling seborrheic skin
eruptions + hepatosplenomegaly,
lymphadenopathy, pulmonary lesions,
osteolytic bone lesions → anemia and
thrombocytopenia, reccurent infections
metastasis
• osteolytic x osteoplastic
• prostate, breast, stomach, lung cancer
bone marrow necrosis
• ischemia:
– vascular collaps in hypercellular marrow
– metastatic obstruction
– sickle cell disease, DIC...
• symptoms: pain, fever, hematopoietic
precursors in peripheral blood
transplantation
• transplantation: bone marrow, peripheral
stem cells
• autologous x allogenneous (relatives, nonrelatives)
• indications:
– hematological: tumours, immunodeficiency,
anemias, b.m. aplasia
– non-hematological: tumour metastasis
transplantation
•
•
•
•
bone marrow suppression → graft
hypocellularity → proliferation
immunosuppression!
GvHD acute x chronic:
– skin, intestine, liver
Bleeding disorders
•
•
•
•
cause:
defect in the vessel wall
platelet deficiency or dysfunction
coagulation factors disorder
bleeding disorders...vascular
A) defects in the vessel wall
1) hereditary
a) m. Osler-Rendu-Weber (hereditary
hemorhagic teleangiektasias)
– capillary aneurysms in the skin and mucous
membranes
b) connective tissue disorders
 m. Ehlers-Danlos
 Marfan´s syndrome
bleeding disorders...vascular
2) acquired
a) avitaminosis C, ↑ corticosteroids
– cutaneous, intramuscular, mucosal bleeding
b) purpura Henoch-Schönlein
– circulating IC → skin, kidney
bleeding disorders...plateles
B) plateles deficiency or dysfunction
1) thrombocytopenia
a) decresed production
 aplastic anemia
 hereditary disorders (sy BernardSoulier, grey-plateles sy, m. WiskottAldrich)
bleeding disorders...plateles
b) increased destruction
 splenomegaly, arteficial valves,...
DIC (disseminated intravascular
coagulation)
– activation of the coagulation sequence, leading
to formation of thrombi throughout the
microcirculation → consumption of plateles
and coagulation factors and secondarily
activation of fibrinolysis
bleeding disorders...plateles
thrombotic thrombocytopenic purpura
(TTP)
– thrombocytopenia, fever, microvessel
obstruction symptoms
– → microangiopathic hemolytic anemia
– hyaline thrombi in the microcirculation
hemolytic-uremic syndrome (HUS)
– E.coli
– kidney cortex necrosis, intestinal bleeding
bleeding disorders...plateles
idiopathic thrombocytopenic purpura (ITP)
– autoimmune origin
– destruction in the spleen → splenectomy
– bm +/- increased megakaryopoiesis
bleeding disorders...plateles
2) platelet dysfunction
 adhesion disorder (Bernard-Soulier, m. von
Willebrand)
 aggregation disorder (thrombasthenia
Glanzmann)
 secretion disorder: tromboxan A2
inhibition (aspirin)
bleeding disorders...
coagulation factors
C) coagulation disorders
1) hereditary deficiencies
a) hemophilia A (classic hemophilia)
– f VIII (severe = activity < 1%!)
– X chromosoma (new mutation x familiar)
– easy bruising and massive hemorrhage after
trauma or operative procedures,
„spontaneous“ hemorrhages – joints
(hemarthroses) → progressive deformities
b) hemophilia B (Christmas disease)
– f IX
bleeding disorders...
coagulation factors
2) acquired
a) DIC
b) liver diseases
• synthesis of coagulation factors
(fibrinogen, prothrombin, fV, VII, IX-XI)
+ anticoagulation and fibrinolytic factors
c) vitamin K
• food, synthesis in the large intestine
(bacterias)
d) anticoagulation therapy
lymph vessels and nodes
lymphatic vessels
A) lymphoedema
• lymph is protein-rich → lymphostasis leads
to fibroproduction, +/- infectious and
ulcerative complications
1) hereditary = Milroy´s disease
• valvular disorder
2) acquired lymphoedema
• lymphoedema praecox
• secondary lymphoedema: obstruction and
lymphostasis (mlg, inflammatory changes)
lymphatic vessels
B) lymphangiectasia
• focal extension of lymphatic vessels
• skin, small intestine (chylangiectasia)
• → lymforhea (chylothorax...)
lymphatic vessels
C) lymphangiitis
• lymph vessels draining the primary
(infectious) focus
• β hemolytic streptococci
• + regional lymphadenitis
• clinical: red subcutaneous line
• histology:
– lymphangiitis simplex
– lymphangiitis purulenta: pus + fibrin →
spreading → abscesses, trombophlebitis
lymfatic nodes...structure
• cells: lymphocytes, dendritic cells (FDRC,
IDRC), macrophages with apoptotic bodies,
NK cells
• follicles = B zone
– lymphocytes from the bm → primary follicle
→ immunity stimulation → germinal centres =
secondary follicle, immunity answer →
polarization of germinal centres
– germinal centres: B cells augmentation,
selection Ag high affinity clones → plasma
cells differentiation → migration into medulla,
waiting to secondary immunity answer
lymph nodes...structure
• medulla
– lymphatic tissue between medullar sinuses
– small lymphocytes, plasma cells
• paracortex = T zone
– mainly CD4 T cells, small venules
– T lymphocytes 70% of lymphocytes in lymph
node and 80-90% in blood
• sinuses
– incoming lymph vessels → subcapsular
(marginal) sinus → interfollicular → medulla →
outgoing vessels
lymph nodes...regressive changes
A) regressive changes and circulatory
disorders
1) infarction
• vasculitis
• tumorous infiltration
 vascular transformation of sinuses
2) atrophy
• lipomatous
• hyalin
3) pigmentation
4) amyloidosis
5) storage diseases
lymph nodes...inflammation
B) lymphadenitis
1) acute nonspecific
• inflammation of regional lymph node
• clinicaly: enlarged, erythematous lymph
nodes
• histology: ↑ follicles, mitoses, sinuses
filled with granulocytes, histiocytes
• +/- healing with fibrous scarse
lymph nodes...inflammation
2) chronic nonspecific lymphadenitis
• etiology:
a) follicular hyperplasia
• etio: tonsillitis, respiratory infections,
RA, syphilis, AIDS
• histology: ↑ germinal centers, fanciful
shapes, many mitoses, blastic forms of
cells – could be misinterpreted like mlg
lymphoma!
lymph nodes...inflammation
progressive transformation of germinal
centres
– connection with HD (paragranuloma)
m. Castleman (angiofollicular hyperplasia)
– „lolly pops“ follicles
– unifocal bng x multifocal fatal
lymph nodes...inflammation
b) paracortical hyperplasia
• etio: viruses (IM, HSV), inoculation, some
drugs
• histology: enlarged paracortex, with many
IDRC, small follicles in the periphery of
the lymph node, T imunoblasts
c) reactive sinusoidal histiocytosis
• etio: reactive (different Ag)
• histology: dilated sinuses filled with
histiocytes
lymph nodes...inflammation
m. Rosai-Dorfman (masive sinusoidal
histiocytoses)
– intrasinusoidal macrophages with
emperipolesis
d) mixed reactive hyperplasia
• etio: toxoplasmosis (epitheloid granulomas)
lymph nodes...inflammation
3) granulomatus purulent
• epitheloid granulomas with central
necrosis with accumulation of neutrophils
cat scratch disease
veneric lymphogranuloma (Chl.trachomatis)
mesenterial lymphadenitis
(Y.enterocolitica)
ulcus molle (H. ducreyi)
lymph nodes...inflammation
4) granulomatous necrotic
tularemia (Fr. tularensis)
plague (Y. pestis)
anthrax (B. antracis)
5) granulomatous
• tuberculoid granulomas without central
necrosis
sarcoidosis, m. Crohn...
6) TBC lymphadenitis
• miliary x caseous productive
lymph nodes...inflammation
7) granulomatous reaction to lipid
materials
m. Whipple
– lipid vacuoles, around epitheloid
histiocytes, intracytoplasmic PAS+ material
8) granulomatous reaction to foreign
bodies
• silicic material in prosthesis
lymph nodes...neoplasms
lymph nodes...neoplasms
C) neoplasms, malignant lymphomas
1) m. Hodgkin (HD)
• group of disesases
• presence of distinctive neoplastic giant
cells: Reed-Sternberg cells, Hodgkin cells,
admixed with a variable infiltrate of
reactive, nonmalignant inflammatory cells
• young people
lymph nodes...neoplasms...HD
• classification:
 nodular lymphocytic predominance
Hodgkin lymphoma
• „classic“:
 lymphocyte rich HL (LR-CHL)
 nodular sclerosis (NS-CHL)
 mixed cellularity (MC-CHL)
 lymfocyte depleted (LD-CHL)
lymp nodes...neoplasms...NHL
2) non Hodgkin lymphomas
• predominance of neoplastic cells
• elder patients
• B and T cells
lymph nodes...neoplasms...B-NHL
a) B-NHL
 chronic lymphocytic leukaemia/small
lymphocytic lymphoma (CLL/SLL)
 follicular lymphoma (FCL)
 mantle cell lymphoma (MCL)
 marginal zone lymphoma (MZL): SMZL,
ENMZL=MALT, NMZL
 hairy cell leukaemia (HCL)
 diffuse large B-cell lymphoma (DLBCL)
 Burkitt lymphoma
chronic lymphocytic
leukaemia/small lymphocytic
lymphoma (CLL/SLL)
• elderly patients
• naive lymphocytes
• indolent type of lymphoma
follicular lymphoma (FCL)
• middle aged patients
• centrocytes and centroblasts
• indolent course but rellapsing!
mantle cell lymphoma (MCL)
• „diffuse centrocytoma“
• agressive type of lymphoma
• t(11;14) – cyklin D1
marginal zone lymphoma (MZL)
• mucosa associated lymphoid tissue
(MALT) – GIT, bronchi…
• association with chronic inflammation
diffuse large B-cell lymphoma
(DLBCL)
• „waste basket“
• transformation of small cell
lymphomas
• aggresive course x good reaction to
therapy
Burkitt lymphoma
• endemic x sporadic
• younger patients
• association with EBV infection
lymph nodes...neoplasms...B-NHL
• plasma cell neoplasms:
 monoclonal gammopathy of
undetermined significance (MGUS)
 lymphoplasmacytic lymphoma (LPL), m.
Waldenström
 plasmacytoma
 multiple myeloma
lymph nodes...neoplasms...T-NHL
b) T-NHL
 peripheral T cell lymphoma (PTL)
 anaplastic large T cell lymphoma (ALCL)
 angioimmunoblastic T cell lymphoma
(AILT)
 adult T cell leukaemia
 mycosis fungoides/Sezary syndrom
anaplastic large T cell
lymphoma (ALCL)
• young patients
• typical translocation t(2;5)
mycosis fungoides/Sezary
syndrom
• primary skin lymphoma →
generalisation = Sezary syndrom
spleen
spleen
• structure:
– white pulp: lymphoid tissue
– red pulp: venous sinuses → hilus
• splenomegaly: venosthasis, inflammation,
neoplasms
• hypersplenism = increased function →
cytopenia
• hyposplenism → susceptibility to certain
bacterial infections
spleen...regressive changes,
circulatory disorders
A) inborn anomalies
• accessory spleens = spleniculi
B) regressive changes and circulatory
disorders
1) amyloidosis
• secondary (AA)
• +/- hyposplenism
spleen...regressive changes,
circulatory disorders
2) storage diseases
3) hemolytic anemias
• ↑ splenic function → splenomegaly
• hereditary spherocytosis
4) chronic perisplenitis
5) splenic infarction
• white (embolization, vasculitis)
• red (thrombosis of lienal vein)
spleen...regressive changes,
circulatory disorders
6) chronic venosthasis
7) splenic rupture, bleeding
• traumatic
spleen...inflammation
A) inflammation
1) acute septic tumour
• reaction to general infection x tumour
lysis
• clinically: tense capsula, soft tissue
• histology: red pulp cellular, small
abscesses (central pyemia)
spleen...inflammation
2) chronic inflammatory tumour
• chronic infections (IE)
• histology: red pulp hyperemia, reactive
hyperplasia of the white pulp
• malaria
• TBC, histoplasmosis, leishmaniosis,
trypanosomiasis
• AIDS
spleen...tumours
D) tumours and pseudotumours
1) cystic formations
• posttraumatic pseudocysts
• parasitary cysts
2) hamartoma (splenoma)
• nodule
• histology: chaotic sinuses a fibrous tissue =
incorrect arrangement of the red pulp
• +/- hypersplenism
spleen...tumours
3) hemangioma
• histology: cavernous blood spaces,
thrombosis
4) littoral cell angioma
• phagocytosis → pancytopenia
5) inflammatory pseudotumour
• histology: inflammatory cells +
fibroproduction
spleen...tumours
6) malignant lymphomas
• primary: SMZL
• secondary:
• more often
• secondary infiltration by NHL, HD, CML,
HCL
7) epithelial metastasis
• microscopically
thymus
thymus...structure
• structure:
• lobulus
• cortex and medulla mixture of T
lymphocytes and a epithelial cells =
lymphoepithelial organ
• cortex: mainly T lymphocytes
• lymphatic follicles without germinal
centres
• medulla: thymocytes, Hassal bodies
thymus...function
• function:
– production of small lymphocytes with cellular
immunity
– TdT a CD1 → maturation → CD4 a CD8 →
postthymic lymfocytes in medulla: CD4
(helpers/inducers), CD8
(suppressor/cytotoxic), loss of TdT a CD1 →
blood, peripheral lymphatic organs
• main role intrauterine and in childhood
thymus...dysgenesis
A) thymic dysgenesis
• primary immunodeficiency syndromes
(diGeorge, Nezelof...)
thymus...regressive changes
B) regressive changes
1) lipomatous atrophy (involution)
• puberty – involution with increase of
adipous tissue = ↓ thymocytes,
calcification of Hassal bodies...
2) acute (accidental) involution
• etio: corticosteroids – stress
• histology: fragmentation of cortical
thymocytes, cystic transformation of
Hassal bodies, lymfocytes disappeared, in
cortex only spindle epithelial cells
thymus...hyperplasia
C) thymic hyperplasia
primary hyperplasia
myasthenia gravis
• histology: lymphoid hyperplasia, lymphatic
follicles with germinal centres
• Ab anti acetylcholin-receptors
thymus...neoplasms
D) neoplasms
1) thymomas
• epithelial thymic cells + lymphocytes
• local manifestation
• association with myasthenia gravis
2) neuroendocrinne tumors
3) germinal cells tumours (teratoma,
seminoma)
• bng, cystic
4) malignant lymphoma