The use of leukocyte acid phosphatase in the diagnosis of malignant disease. Case report and review of literature.

Tartrate resistant acid phosphatase (TRAP) has been demonstrated during relapse in the cells in the cerebral spinal fluid (CSF) in a patient with the clinical features of acute T cell lymphocytic leukemia which suggests this isozyme may be a marker for malignant transformation of some types of lymphocytes. The presence of TRAP may be helpful in establishing the diagnosis of a lymphocytic malignancy since normal lymphocytes appear to have tartrate sensitive acid phosphatase. The presence of TRAP can no longer be considered specific for hairy cell leukemia, since children with acute lymphocytic leukemia are being found with this isozyme in their malignant blasts. The presence of TRAP does not appear to be specific for T or B cell lines of malignant lymphocytes since it has been described in cells with either type of cell markers. The presence of TRAP seems most useful in differentiating lymphocytic malignancies from monocytic and histiocytic malignancies and from benign lymphocytoses when the cells of the peripheral blood and marrow may have similar morphologic features with routine staining.