Primary cutaneous γ/δ T-cell lymphoma presenting as disseminated pagetoid reticulosis

The first case of primary γ/δ cutaneous T-cell lymphoma (CTCL) with a fatal outcome is reported. The patient had the clinical and histopathologic features of disseminated page told reticulosis, a rare form of CTCL characterized by a strong epidermotropic lymphoid infiltrate. Extensive immuno-cytochemical studies showed that the neoplastic cells were almost exclusively localized in the epidermis, expressed the γ/δ variant of the T-cell receptor (CD3⁺, TCR-δ-1⁺) and were CD5⁺, CD7⁺, CD27⁺, CD29⁺, CD43⁺, CD44⁺, CD45⁺, CD45RA⁺, CD54⁺, CD69⁺, but βF1^-, Tiγa^-, BB3^-, A13^-, CD2^-, CD4^-, CD8^-, CD11a ^-, CD49d^-, CD25^-, CD30^-, and HLA-DR^-. A comparison of our results with those of the literature, which have not included γ/δ T-cell receptor analysis, suggests that some reported cases of pagetoid reticulosis may have phenotypes similar to our case. Electron microscopy studies demonstrated that the γ/δ T lymphocytes were villous, containing dense and multivesicular bodies, and formed close contacts with the surrounding keratinocytes, suggesting that these cells should have a role in the skin-associated lymphoid tissue. The proliferating cells in our case might represent the neoplastic counterpart of the recently reported CD2^- subset of normal human peripheral blood γ/δ T lymphocytes.