[Dermatofibrosarcoma protuberans developing for 25 years with 27 recurrences. Histological and ultrastructural study]

The authors report the results of a histological and ultrastructure study of a case of a protuberant dermatofibrosarcoma evolving for the last 25 years with 27 relapses. Histologically the tumour is dermic, non-encapsulated, invading the hypodermis right from the beginning and mainly made up of fusiform cells which often have a storiform appearance and proliferate in a varying degree of collagenous stroma which includes an oedematous or myxoid component. During the course of the evolution of this tumour, there were zones of cystic degeneration, but in the last 10 relapses in 1978 and 1979, we noted the predominance of cellular and compact zones with an increase in the number of mitoses. The ultrastructure study showed tumour cells containing a fairly well developed endoplasmic reticulum in the cytoplasm, a prominent Golgi apparatus and some pinocytic vesicles. Some of the cells also contained lysosomes and phagolysosomes, whereas others contained cytoplasmic filaments and contractile elements. The nuclei were in general elongated and irregular. Sometimes the cytoplasmic membrane was covered by an amorphous substance with a membranoid appearance. Between the cells sometimes there were junctions of the tight kind. In conclusion, the authors consider that this tumour has the histological characteristics of a protuberant dermatofibrosarcoma and at the ultrastructure level, it is made up of cells which put it in the group of myofibroblastic and histiocytic proliferating lesions.