[Histochemical and electron microscopical studies of histiocytoma (author's transl)]

In histiocytomas the alkaline phosphatase technique reveals a surprising number of capillaries. The capillaries branch out from the center to the periphery of the histiocytoma and even the capillaries beneath the epidermis proliferate. The cellular elements outside the capillaries, however, are fibroblasts, histiocytes and mast cells, as is revealed by various histochemical and electron microscopical examinations. Histiocytomas of short duration differ from older histiocytomas in that the former contain fibroblasts similar to those found in healing wounds (C-fibroblasts).