[Composite lymphoma: Case report of a coexisting follicular and mantle cell lymphoma in situ in a cervical node].

Composite lymphoma represents 1-4% of lymphomas. Only 8 case reports concerned coexisting follicular lymphoma and mantle cell lymphoma. Here, we report the case of an 81 years old man who has been diagnosed with a composite follicular and in situ mantle cell lymphoma. The use of a large panel of immunohistochemical stains associated with the flow cytometry results have allowed us to make this particular diagnosis. We highlight here a common clonal origin of the composite lymphoma's two entities, as described in previous publications.