spleen and thymus

Question 1

red pulp

Answer 1

traversed by numerous thin walled sinusoids separated by cords of billroth
endothelium lining sinusoids discontinuous

Question 2

cords

Answer 2

contain labyrinth of macros loosley connected vi along dendritic processes
physical and functional barrier

Question 3

open circulation

Answer 3

thru capillaries into cords -> sinusoids

only small percentage, but over course of the day filters entire blood volume

Question 4

closed circuit

Answer 4

blood passes rapidly and directly from capillaries into splenic vv

Question 5

white pulp follciles

Answer 5

artery w/eccentric collar of T cells -> periarteriolar lymphatic sheath
at intervals the sheath expands to from lymphoid nodules of B cells which can create germinal centers

Question 6

functions of spleen

Answer 6

phagocytosis of blood cells and particulate matter
Ab production
hematopoiesis
sequestration of formed blood elements

Question 7

phagocytosis of blood and partciulates

Answer 7

red cells that get stuck are phagocytosed by macros

Question 8

pitting of RBC

Answer 8

process by which splenic macros excise inclusions to remove particles such as bacteria from blood

Question 9

Ab production

Answer 9

DCs in periarterial lymph sheath trap Ags present to T cells which activate B cells which mature to Ab producing plasma cells in red pulp

Question 10

hematopoiesis

Answer 10

fetal

compensatory extramedullary

Question 11

sequestration of formed blood elements

Answer 11

splenomegaly can cause an increase in WBCs stored in spleen -> thrombocytopenia, leukopenia

Question 12

aplenic suscpeitble to

Answer 12

S. pneumoniae
Mengiococcal
H. influenza

Question 13

hyperspenism

Answer 13

anemia
leukopenia
thrombocytopenia

Question 14

non specific acute splenitis

Answer 14

blood borne infection

due to microbes themselves and cytokines

Question 15

non specific acute splenitis morphology

Answer 15

200-400gm and soft
acute congested red pulp, may encroach and efface lymph follicles
neutrophils, plasma cells, and eos may be in white and red pulp
white pulp may undergo necorsis
rarely abscesses form

Question 16

congestive splenomegaly

Answer 16

due to chornic venus outflow obstruction

Question 17

systemic or central venous congestion

Answer 17

cardiac decompensation (right)
spleen rarely exceeds 500gm

Question 18

cirrhosis of liver

Answer 18

main cause of massive congestive splenomegaly
schistosomiasis causes pipe-stem massive fibrosis
diffuse cirrhosis of alcoholics and pigment cirrhosis also cause profound enlargement

Question 19

spontaneous portal v thrombosis

Answer 19

associated w/intrahepatic obstructive disease or inflammation of portal v after intraperitoneal infections

Question 20

morphology of congestive splenomegaly

Answer 20

long standing congestion produces marked enlargements
organ firm, capsule thickened fibrotic
red pulp fibrotic and cellular
elevated protal venous pressure stimulates collagen deposition in BM of sinusoids -> appear dilated
excessive destruction of RBCs

Question 21

CA associated w/splenomegaly

Answer 21

HL
NHL 
lymphocytic leukemias
MM
MPD

Question 22

Inflammatory conditions associated w/splenomegaly

Answer 22

RA

SLE

Question 23

storage disease associated w/splenomegaly

Answer 23

gaucher disease
Niemann-picj
mucopolyaccharidoses

Question 24

splenic infacts

Answer 24

common lesions due to emboli usually from heart

Question 25

bland infarcts

Answer 25

pale, wedge shaped, subcasular | overlying capsule covered w/fibrin

Question 26

septic infarcts

Answer 26

supportive necorsis | large depressed scars when healed

Question 27

neoplasm of spleen

Answer 27

rare except in meyloid and lymphoid tumors

Question 28

benign tumors or spleen

Answer 28

``` fibrosma osteomas chondroma most common are lymphangioms and hemangiomas often cavernous ```

Question 29

infections that increase risk of splenic rupture

Answer 29

mono malaria typhoid fever lymphoid neoplams

Question 30

thymus cortical epithelium

Answer 30

polygonal | abundant cytoplasm w/dendritic extensions that contact adjacent cells

Question 31

thymus medullary epithelium

Answer 31

densely packed often spindle shaped and scant cytoplasm | no interconnecting processes

Question 32

hassel corpuscles

Answer 32

whorls of medullary epi with characteristic keratinzed cores

Question 33

thymic hypoplasia

Answer 33

DiGeroge syndrome severe defects in T cell immunity other defects due to 22q11 deletion

Question 34

isolated thymic cyts

Answer 34

uncommon lesions discovered incidentally lined by stratified or columnar epi serous or mucinous can be secondary to CA so if symptomatic should be investigated

Question 35

thymic hyperplasia

Answer 35

appearance of B cell germinal centers w/in thymus more correctly termed thymic follicular hyperplasia

Question 36

causes of thymic follicular hyperplasia

Answer 36

``` chronic inflammatory and immunological states Most frequently due to myasthenia gravis SLE scleroderma RA ```

Question 37

thyomas

Answer 37

tumors of thymic epi

Question 38

suptypes of thyomas

Answer 38

cytologically benign and noninvasice cytologically benign but invasive cytologcially malignant (thymic carcinoma)

Question 39

thyoma stats

Answer 39

rare in kids M=F most in superior mediastinum sometimes occur in neck, thyroid, pulmonary hilus or elsewhere

Question 40

thyomas morphology

Answer 40

lobulated, firm gray-white areas of cystic necrosis and calcification most encapsulated, but can rupture and infiltrate perithymic tissues and structures

Question 41

non invasive thyomas

Answer 41

medullary type epi or mixture of medullary and cortical | spare inflitrate of thymocytes

Question 42

invasive thyomas

Answer 42

coritcal epi w/abundant cyto and rounded vesicular nuclei numerous thermocytes sometimes cytological atypia ruptures thru capsule

Question 43

thymic carcinoma

Answer 43

fleshy obviously invasive mets to lung squamous cell carcinomas are most common lymphoepithlioma-like carcinomas next most common

Question 44

lymphoepithlioma-like carcinomas

Answer 44

sheets of cells w/indistinct borders close histological resembles to nasopharyngeal carcinoma 50% EBV

Question 45

thyomas clinical

Answer 45

40% present with symptoms due to impingement on mediastinal structures 30-45% detected while evaluating myasthenia gravis

Question 46

autoimmune conditions associated w/thyomas

Answer 46

``` MG hypogammaglobulinemia pure red cell aplasia graves disease pernicious anemia dermatomyositis-polymyositis cushings ```