Histochemistry of Kaposi's sarcoma. I. Hydrolases and phosphorylase

Hydrolases and phosphorylase were demonstrated histochemically in six specimens of Kaposi's sarcoma obtained from three patients. The linings of the vascular slits were lacking in alkaline phosphatase activity. The spindle-shaped or stellate cells adjoining the vascular slits showed little or no alkaline phosphatase activity but high unspecific esterase and moderate acid phosphaatase activities. The spindle cells of the compact bundles of the tumor displayed a slight to moderate esterase activity and little or no reaction for phosphatases. All specimens displayed an intense over-all aminopeptidase activity, but no phosphorylase was demonstrable. The authors suggest that the spindle cells of the vascular slits and those of the bundles represent two functional stages of multipotent mesenchymal cells. The former have a “reticulo-endothelial” function, i.e., phagocytosis and formation of reticular fibers; the latter acquire a fibroblastic character.