Primary Cutaneous Peripheral T-Cell Lymphoma With Follicular Helper T-Cell Phenotype: Report of 2 Epstein-Barr Virus-Positive Cases.

Primary cutaneous T-cell lymphoma is distinct from nodal T-cell lymphoma clinically and pathologically. Recently, primary cutaneous follicular helper T-cell lymphoma (PC-TFHL) has been described as a peripheral T-cell lymphoma with T-follicular helper (TFH) cell phenotype. PC-TFHL usually presents as multiple plaques and nodules of skin with an indolent clinical course, but without association with Epstein-Barr virus. In this article, we report 2 rare cases of PC-TFHL which are Epstein-Barr virus-positive and with an aggressive clinical course. We discuss the challenges in the differential diagnoses, particularly with primary cutaneous extranodal NK/T-cell lymphoma, and nodal T-cell lymphoma of TFH origin with secondary cutaneous involvement.