Image Description
MALT Lymphoma - Transformation to Diffuse Large B-cell Lymphoma (DLBCL): MALT lymphomas are low-grade, indolent B-cell tumors that can transform in <10% of cases to more aggressive DLBCL. The transition phase may show composite lymphoma with fields of clonally related small and large cells areas.
Discrete large transformed cells with morphology of centroblasts or immunoblasts are usually present in MALT lymphomas in small numbers. However, if they form solid aggregates, nodules or confluent sheets, the diagnosis of DLBCL should be considered. Necrosis is rarely seen in MALT lymphomas and its presence should also alert one to the possibility of transformation to DLBCL. The presence or absence of MALT lymphoma and the relative proportion of both components (MALT lymphoma & DLBCL) should be mentioned in the report.
The image shows a DLBCL that arose in a thyroid MALT lymphoma.
Discrete large transformed cells with morphology of centroblasts or immunoblasts are usually present in MALT lymphomas in small numbers. However, if they form solid aggregates, nodules or confluent sheets, the diagnosis of DLBCL should be considered. Necrosis is rarely seen in MALT lymphomas and its presence should also alert one to the possibility of transformation to DLBCL. The presence or absence of MALT lymphoma and the relative proportion of both components (MALT lymphoma & DLBCL) should be mentioned in the report.
The image shows a DLBCL that arose in a thyroid MALT lymphoma.