Thymus and Spleen Flashcards
Thymic hemorrhage
>dogs: sudden death due to hypovolemic shock resulting from massive thymic/mediastinal hemorrhage
>causes: trauma, ruptured aorta, anticoagulant rodenticide
Thymic lymphoma
-neoplastic proliferation of T-lymphocytes
-younger animals (cats, calves, dogs)
-malignant behaviour
Thymoma
-neoplastic proliferation of epithelial cells
-dogs, sheep, goats
-slowing growing, encapsulated
Siderofibrosis of splenic capsule=gamna-gandy bodies
-incidental finding
-possible sequela of prior hemorrhage
*granulare white-yellow deposits in splenic CAPSULE
Splenic amyloidosis
-usually secondary amyloidois: chronic inflammation
*splenomegally, beige to orange discolouration
Splenic contraction
-occurs with catecholamine release, shock, acute splenic rupture
*small dry spleen with wrinkling of capsule
Incomplete splenic contraction
*grossly similar to splenic infarction
Splenic rupture
Splenic rupture leading to splenosis
*small red nodules within omentum
Splenic torsion
-dogs and pigs
*splenomegaly, blue to black, folded back on itself
Active hyperemia and passive congestion
*spenomegaly, dark blue or black, oozes blood on cut surface
Splenic infarcts
-thrombois:
>vascular damage
>hypercoagulable states
>splenomegaly
-septic emboli
*discrete, raised, and dark red
*chronic: pale, depressed and firm
Splenic hematoma
*large, soft, dark red nodular mass
NEED histology to rule OUT underlying neoplasia
-COMMON in dogs
Acute splenitis: multifocal necrotic OR suppurative splenitis
-Tularemia or Yersiniosis
*multifocal miliary WHITE foci within the spleen
>sometimes lymph nodes and liver
>older lesions: resemble granulomas/abscesses
Acute splenitis: Septicemic splenitis
-african swine fever
-erysipelas
-anthrax
*splenomegaly, dark, engorged with VISCOUS blood
Nodular granulomatous splenitis (chronic)
Diffuse granulomatous splenitis (chronic)
Spleen abscesses
-rare
-Trueperella pyogenes OR rhodococcus equi
Benign nodular hyperplasia
-common in older dogs
-incidental finding
-may predispose splenic hematomas
*red and white nodular masses, composed of lymphoid tissue and red pulp
Lymphoid hyperplasia
-hyperplasia of white pulp
-response to blood-borne chronic antigenic stimulation
Splenic hemangioma
-benign tumour of endothelial origin
*single, soft, dark, red nodular mass
HISTOLOGY NEEDED: looks similar to splenic hematoma and hemangiosarcoma
Splenic hemangiosarcoma
-most common malignant tumour of canine spleen
*single to multiple discerte to coalescing masses, dark red, +/- metastases
Tonsils and MALT
-constantly stimulated
*important site of entry for pathogens
