Malignant histiocytosis of the intestine: report of three cases with immunological and cytochemical analysis.

Tumour cells from three cases of malignant histiocytosis of the intestine (MHI) have been studied immunologically and cytochemically. The cells did not form E rosettes and showed weak Fc gamma surface receptors. They contained non-specific esterase and acid phosphatase in diffuse granular distribution. In one case tumour cells showed no staining by an immunoperoxidase technique with two monoclonal anti-T cell antibodies but positive staining with a monoclonal anti-Ia-like antibody. The malignant cells from all three cases could be shown to contain alpha-1-antitrypsin. These are the first cases of MHI to have been studied in this way and the results confirm the true histiocytic--that is, monocyte/macrophage, derivation of the tumour cells in this disease.