[Transformation of Follicular Lymphoma into Composite Lymphoma: A Case Report and Literature Review]

Follicular lymphoma is a relatively indolent B-cell lymphoma composed of neoplastic centrocytes and centroblasts. The histologic transformation of follicular lymphoma is a well-described phenomenon with an average risk of 30% at ten years. The occurrence of Hodgkin lymphoma after follicular lymphoma, as well as composite lymphoma, is extremely rare. We report the case of a 79-year-old man with generalized lymphadenopathy who was diagnosed with follicular lymphoma and treated with six cycles of R-CHOP with a complete response. A lymph node biopsy three years later revealed persistent follicular lymphoma, after which the patient received radiotherapy. The patient returned with progressively enlarging axillary lymph nodes five years later. A lymph node biopsy demonstrated a composite lymphoma that was consistent with follicular lymphoma and Hodgkin lymphoma.