Orbital soft tissue composite lymphoma presenting as recurrence of a nodal lymphoma with mantle and follicular cell components: A case report, literature review and guideline for the treatment of patients.

Composite lymphoma with mantle and follicular cell components is a challenging diagnosis. Flow cytometry, immunohistochemistry and molecular genetics are required to distinguish the two components, as often the more aggressive one is predominant and masks the other. A 58-year-old man with history of nodal composite lymphoma presented with right exophthalmos and diplopia. A head CT scan showed an orbital tumor. A biopsy of the tumor revealed a mantle cell lymphoma predominating over a follicular lymphoma. Immunoglobulin heavy chain and light chain rearrangements analysis by PCR proved that both components of the orbital tumor were recurrences of the same nodal composite lymphoma diagnosed two years earlier. The nodal lymphoma was composed of a follicular lymphoma and an in situ mantle cell neoplasia. Consensus view is that dominant lymphoma should be treated when needed but taking into account if the mantle cell lymphoma is an in situ neoplasia and if it expresses CD5 and SOX11.