Sézary syndrome. Tartrate-resistant acid phosphatase in the neoplastic cells.

Tartrate-resistant acid phosphatase has been known to be of diagnostic value in hairy cell leukemia. However, occasionally neoplastic cells of other varieties of lymphoproliferative disorders may contain tartrate-resistant acid phosphatase. The authors have studied four patients with Sézary syndrome who had typical cutaneous lesions with extensive lymphoid infiltrates and circulating atypical E-rosetting lymphoid cells. The abnormal Sézary cells accounted for 23-69% of the peripheral mononuclear cells and often showed convoluted or folded nuclei. These cells in all four patients were strongly positive for acid phosphatase resistant to tartaric acid inhibition. Enzymatic cytochemical studies for acid phosphatase with and without tartrate may be helpful in the differential diagnosis of cutaneous T-cell lymphomas from variants of chronic dermatitis.