[Subclinical spread of dermatofibrosarcoma protuberans and resulting treatment modalities]

Dermatofibroma protuberans is a rare malignant tumour with a high rate of local recurrence. This is attributable to the tumour's characteristic of forming subclinical, pseudopodium-like outgrowths. Between 1981 and 1991 we treated 23 cases of dermatofibrosarcoma (9 primary tumours, 14 recurrences of tumours following initial treatment elsewhere) using the method of micrographic surgery with paraffin sectioning. Tumour size and localization were taken as parameters, along with the excision depth and the safety margin required for elimination of all tumour cells. The safety margin required for complete extirpation ranged from 5 to 60 mm. On average, recurring tumours infiltrated twice as far beyond the clinically visible tumour margin (22.4 mm) as primary tumours (10.0 mm). Up to now, no localized recurrences have been found in any patient. The therapy used here can be designated as the method of choice.