[Pseudoangiosarcoma (Masson). A histological study (author's transl)]

The following is a report about two cases of pseudoangiosarcoma (Masson). The pseudoangiosarcomatous changes developed in one case in a cavernous hemangioma and in the other on the heel, presumably in the lumen of a vessel of the dermis. In our opinion thrombosis precedes the pseudoangiosarcomatous proliferation, which can be interpreted as a manifestation of a peculiar form of the organization of thrombotic material. Another possibility is discussed namely that the papillary endothelial proliferation is the earliest event in the formation of pseudoangiosarcoma.