Clinical and pathological spectrum of CD8-positive cutaneous T-cell lymphomas

CD8+ T-cell lymphomas presenting in the skin are rare. We describe the clinical and histological features of 18 patients with CD8+ cutaneous T-cell tumors, which have been divided into four groups. Seven patients had precedent long histories of rashes, which progressively spread in a presentation similar to that of CD4+ mycosis fungoides (MF). Three patients had long-standing localized plaques consistent with a pagetoid reticulosis (PR) pattern. Two patients presented with erythroderma and had peripheral blood involvement consistent with a Sezary syndrome (SS) pattern and had rapidly progressive clinical courses. Six patients presented with cutaneous nodules of varying sizes and had variable outcomes, with two having rapidly progressive disease, two with indolent recurrences and a further two with complete responses to treatment. Histologically, 12 of the 18 cases showed an epidermotropic tumor infiltrate that was most marked in the three PR cases. Prominent periadnexal infiltration was seen in 11 cases. Similar to CD4+ MF, the skin-homing antigen, (cutaneous lymphocyte antigen: CLA), was strongly expressed in 13 of 16 tested cases. Expression of the cytotoxic granule protein granzyme B was noted in a majority of tumor cells in only three of 16 tested cases. We conclude that approximately half of CD8+ cutaneous T-cell lymphomas clinically and histologically resemble CD4+ MF/SS, whereas presentation as discrete nodular lesions are more common in CD8+ tumors as compared to those that express CD4.