A unique composite follicular lymphoma and mantle cell lymphoma with a mixed cell pattern and aggressive course

There are a limited number of reports of composite follicular lymphoma (FL) and mantle cell lymphoma (MCL) in the literature, and all previous cases report that FL and MCL components are separated, even within a single lymph node. Here we report a case of a patient with a distinctive composite FL and MCL with a mixed cell pattern.

A 34-year-old man presented with left supraclavicular lymphadenopathy for one month. The lymph node contained closely packed nodules of lymphocytes. Immunostaining and fluorescence in situ hybridization demonstrated the FL nature of the Bcl-2- and CD10-positive tumor cells, as well as the scattered cyclin D1-positive MCL tumor cells in the nodules. Double immunohistochemical staining showed an unusual mixed pattern of both types of tumor cells.

The patient received a regimen of CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone) chemotherapy and achieved partial remission following four cycles of chemotherapy but relapsed 1 month after the last treatment and died of meninges involvement 8 months after the first presentation.

To our knowledge, this is the first report of composite FL and MCL with a mixed pattern. A mixture of grade IIIb FL and MCL may explain the poor prognosis of the patient.