Anatomic Pathology of the Lymphoid System Flashcards
follicles are __________ rich
B cell
what are secondary nodules in lymph nodes like?
germinal center containing large prolifrating lymphocytes
what cells line the sinuses in lymph nodes?
discontinuous endothelium
what are the major reaction patterns in lymph nodes?
hyperplasia
lymphocytolysis/lymphoid necrosis/depletion
inflammation
neoplasia
what is lymphoid hyperplasia of secondary nodules a sign of?
antigenic stimulation
what is the primary feature of lymphocytolysis/necrosis?
apoptosis/necrosis
what causes suppurative- neutrophilic infiltration to abscess formation?
pyogenic organisms
what types of cells usually make up granulomatous reactions?
macrophages and giant cells
neutrophils or lymphoplasmacytic component usually
what is the origin of lymphoma?
lymphocyte
how is lymphoma classified?
location
cell type
cell morphology and tissue architecture
other features
what immunophenotypes match B cell lymphoma?
Pax5
CD79a
CD20
how many non-indolent lymphomas are diffuse large B-cell lymphoma is dogs?
50%
what characterizes non-indolent lymphoma with organs?
often multiple nodes
+/- spleen, liver, GI, other
lung is usually not involved
what does non-indolent lymphoma look like in pathology?
diffuse effacement of nodes by sheets of neoplastic lymphocytes
what is the most common malignancy in cats?
lymphoma
do cats with lymphoma usually have enlarged peripheral lymph nodes?
no
what do about 50% of nasal lymphomas in cats have?
FeLV antigen
what type of lymphoma is most common in horses?
multicentric
what is the adult form of lymphoma is cattle usually due to?
bovine leukemia virus
what are the different forms of lymphoma in cattle?
adult form/enzootic bovine leukosis
multicentric/juvenile form
thymic
cutaneous
what viruses can cause lymphoma in chickens?
marek’s disease
avian leukosis/lymphoid leukosis
what are some tumors that metastasize to draining lymph nodes?
round cell tumors
carcinomas
melanomas
what is splenic pulp divided into?
red pulp
white pulp
what is the white pulp in the spleen?
organized lymphoid tissue: periarticular lymphatic sheath and lymphoid nodules
how common is hyperplasia in the spleen?
very common
what is extramedullary hematopoiesis stimulated by?
regenerative response
what is lyelolipoma?
lipoma mixed with extramedullary hematopoiesis
what are the types of infarct?
acute, hemorrhage
chronic, dry
what are some causes of congestion of the spleen?
venous outflow obstruction
drugs
inflammation necrosis
what are siderotic plaques?
mineralization, fibrosis, and iron deposition in splenic capsule and trabeculae
what is a hematoma in the spleen?
pocket of hemorrhage within spleen forming a mass
what type of cells make up hemangiosarcomas?
endothelial cells
in whom is histiocytic sarcoma common?
bernese mountain dogs
what do trabeculae of the thymus carry?
blood vessels
nerves
efferent lymphatics
what replace the connective tissue found in most lymphoid organs?
epithelial cells
what are hassall’s (thymic) corpuscles?
close packed, flat keratinized cells in concentric arrangement
what is a thymoma?
neoplasm of thymic epithelial cells
