γ/δ T-cell lymphoma involving the subcutaneous tissue and associated with a hemophagocytic syndrome

A case of γ/δ-positive T-cell lymphoma localized primarily in the subcutaneous adipose tissue and associated with an extensive hemophagocytic syndrome and a rapid, fatal outcome is presented. Previous reports of γ/δ cutaneous and subcutaneous T-cell lymphomas are reviewed. To define the characteristics of a T-cell subset of neoplastic cells bearing the γ/δ receptor in a subcutaneous lymphoma, we undertook clinical and laboratory examinations, morphological evaluation of biopsies, electron microscopy, and extensive immunohistochemical studies. Immunohistochemical studies showed that the neoplastic cells expressed the γ/δ T-cell receptor (CD3⁺, CγM1⁺) and were CD2⁺, CD43⁺, CD45⁺, CD45RO⁺, PCNA⁺, but were βF1^-, CD1^-, CD4^-, CD8^-, CD15^-, CD20^-, CD25^-, CD30^-, CD45R^-, CD57^-, CD68^- , Mac 387^-, and HLA Dr^-. To the best of our knowledge, this is the first report of a subcutaneous T-cell lymphoma of γ/δ type involving the subcutaneous tissue and associated with a hemophagocytic syndrome.