SPTCL : Beta F1
Immunophenotype of Subcutaneous Panniculitis-like T-cell Lymphoma (SPTCL): The neoplastic cells are CD3+, CD4-, CD8+ and CD56-. Rare cases are CD4+/CD8- or CD4-/CD8-. They show cytotoxic phenotype and express TIA1, granzyme B, and perforin. By definition, SPTCL should have alpha-beta T-cell phenotype as confirmed by positive staining for Beta F1 (shown here). In recurrent lesions, Beta F1 positivity may be partially lost. Important negative markers include: gamma-delta T-cell receptor, CD30, and EBV. Ki-67 highlights the neoplastic cells clustering around the adipocytes. CD68 is positive in the histiocytic infiltrate within the lesion. T-cell receptor genes are clonally rearranged.