Peripheral T cell lymphoma with a regulatory T cell phenotype: a Mexican case not associated with HTLV-1 virus infection

Peripheral T cell lymphomas are aggressive neoplasms with an overall bad prognosis. As occurred with B cell lymphomas, some T cell lymphomas have been correlated with a normal T cell counterpart. According to the actual WHO classification of tumors of hematopoietic and lymphoid tissues, the only T cell lymphoma characterized by a Treg phenotype is adult T cell leukemia/lymphoma (ATCLL), an entity defined by its etiologic association with HTLV-1 infection. We present a case of peripheral T cell lymphoma with a Treg phenotype not associated with HTLV-1 infection. We describe its pathological and clinical characteristics and discuss the presence of a Treg phenotype in T cell lymphomas.