Splenic Marginal Zone Lymphoma : Differential Diagnosis
The image shows marginal zone compartment in a SMZL. The cells have slightly irregular enlarged nuclei and moderate to abundant pale cytoplasm. Scattered large B-cell resembling centroblasts or immunoblasts are also present. The differential diagnosis of SMZL includes: 1) follicular lymphoma (FL), 2) mantle cell lymphoma (MCL), lymphoplasmacytic lymphoma (LPL), and MALT-type marginal zone lymphoma (MALTOMA). Helpful diagnostic clues: FL is CD10 +ve and shows t(14;18)(q23;q32); MCL is CD5+ve and cyclin D1+ve and shows t(11;14)(q13;q32); about 25%-30% of SMZL show plasmacytic differentiation with serum paraproteinemia and may be difficult to distinguish from LPL; the presence of del 7q favors SMZL over LPL. Bone marrow involvement in LPL is subtle and diffuse; if lymphoid aggregates with marginal zone pattern or intrasinusoidal involvement are seen, it favors SMZL.