Enlargement of the spleen is a requirement for the diagnosis of<unk>  and is seen in nearly all people affected by<unk>  (often without lymphadenopathy). Aside from the uniform involvement of the spleen, the bone marrow is frequently positive in patients with<unk> . Nodal and extranodal involvement are rare. Circulating<unk>  cells are sometimes present in peripheral blood, and they occasionally show short villi at the poles of cells and plasmacytoid differentiation. Autoimmune thrombocytopenia and anemia sometimes seen in patients with<unk> . Circulating villous lymphocytes are sometimes observed in peripheral blood samples. A monoclonal paraprotein is detected in a third of patients without hypergammaglobulinemia or hyperviscosity. Reactive germinal centers in<unk>  white pulp are replaced by small neoplastic lymphocytes that efface the mantle zone and ultimately blend in with the marginal zone with occasional larger neoplastic cells that resemble blasts. The red pulp is always involved, with both nodules of larger neoplastic cells and sheets of the small neoplastic lymphocytes. Other features that may be seen include sinus invasion, epithelial histocytes, and plasmacytic differentiation of neoplastic cells. Involved hilar lymph nodes adjacent to the spleen show an effaced architecture without preservation of the marginal zone seen in the spleen.<unk>  in bone marrow displays a nodular pattern with morphology similar to what is observed in the<unk>  hilar lymph nodes.
Splenic marginal zone lymphoma
Nodal marginal zone B cell lymphoma
Hepatosplenic T-cell lymphoma
Primary mediastinal B-cell lymphoma
Marginal zone B-cell lymphoma
Pediatric-type follicular lymphoma
Duodenal-type follicular lymphoma
Diffuse infiltrative lymphocytosis syndrome