PRF1 and lymphoma: According the WHO classification, the term SPTCL is reserved for α/β T-cell phenotype (but not TCRα/β-rearrangement) lymphomas containing CD8+, granzyme B+, perforin+, TIA1+, CD4- and CD56- cells, which is limited to subcutaneous tissue (no dermal and/or epidermal involvement) and bears relatively good prognosis due to a good response to conservative immunosuppressive regimens.