Composite diffuse large B-cell lymphoma and follicular B-cell lymphoma - case report and review of literature.

Composite lymphoma refers to the co-occurrence of two or more morphologically and immunophenotypically separate lymphomas in the same topographic site at the time of clinical presentation. It is an infrequent type of lymphoid neoplasm, present in lymphoid tissue and may be due to the existence of two genetically related neoplasms such as transformation of a single lymphoma into another more aggressive lymphoma or be due to the presence of two clonally unrelated lymphomas. This paper is presenting a case of diffuse non-Hodgkin large B-cell lymphoma with areas of low grade and high grade follicular non-Hodgkin B-cell lymphoma in a retroperitoneal lymph node and spleen of an 62 year old woman. Histopathological examination and immunohistochemistry features proved the diagnosis of composite lymphoma.