Spleen

Normal Anatomy of the Spleen – Has all the components of the lymph node with a lot of blood flow

Also has the periarterial lymphatic sheath, which is primarily a T cell zone.
Culling of deformed or abnormal RBCs (as they pass through splenic cords) by histiocytes or macrophages.
Big spleens result from same disorders that lead to adenopathy as well as those requiring culling (e.g. hereditary spherocytosis, lyptocytosis), hysiocytosis, or venous congestion.
White pulp is where the normal lymphoid tissue is; Red pulp is the non-lymphoid blood component of spleen.

Causes of Splenomegaly – divided into those of red pulp and white pulp.

Hypersplenism: enlargement of spleen Þ Ý flow of blood through red pulp Þ cytopenia.

Spleen’s big because it overdoses it’s function, therefore look for big spleen in patient with thrompocytopenia, anemia or leukocytopenia

SPLENIC DISORDERS OF RED PULP: which could lead to hyper splenism.

CONGESTIVE: cardiac failure (RBC breaks down Þ Fe into nodules = gamne-gande bodies seen radiographically or histologically in spleen); cirrhosis, congenital disorders of red cells, acute blood-borne infection

INFILTRATIVE

myeloproliferative disorders: Ý spleen due to filtering Ý cells or Extramedullary hematopoiesis due to marrow failure.

lymphoproliferative disorders: Hairy cell leukemia (disorder of clonal B cells that accumulate in spleen)

amyloidosis: spleen has lardacious waxy appearance. Red pulp full of amorphic pink material.

DISORDERS OF CORDAL MACROPHAGES - storage disorders, Gaucher's Disease (histiocytes unable to metabolize glucocerebracide, swell up Þ Ý spleen), histiocytic malignancies

SPLENIC DISORDERS OF WHITE PULP

INFECTIONS: viral - EBV (expansion of T cell zones, see above); parasitic (rare)

LYMPHOID MALIGNANCIES: follicular lymphoma- nodule of lymphoma pepper the spleen

AMYLOIDOSIS

DISORDERS OF WHITE and RED PULP: e.g. Chronic Lymphocytic Leukemia

Anatomic Lesions of the Spleen

CONGENITAL

ASPLENIA: rare, diagnosis from Howel-Jollie bodies on peripheral smear.
ACCESSORY SPLEEN: very common finding. Important when removing spleen due to hypersplenism because accessory spleen will enlarge to compensate therefore hypersplenic state will persist.

INFARCTS: common in patients with infiltrative processes. Tend to be wedge shaped because affect arteries feeding the edge. Painful

RUPTURE: normal spleen does not rupture spontaneously, (results from distention due to EBV, LEUKEMIA etc.)

NEOPLASMS – lymphoma, metastases, hemangiomas (benign neoplasm of the spleen)