[Desmoplastic malignant melanoma. Clinical and histopathologic results of a study in 34 patients].

Clinical and histopathological findings of 34 cases of desmoplastic malignant melanoma (DMM) are summarized and compared to the literature. DMM develop mostly in sun damaged skin of elderly patients, they are rare and often nonpigmented tumors that are difficult to diagnose clinically. In all cases the tumor parameters showed level IV or V melanomas (level IV: 55.9%, level IV-V: 14.7%, level V: 29.4%) and the tumor thickness measured 3.85 mm +/- 2.31 mm (1.0-11.0 mm). In 22 cases, the follow-up time was between 2 and 7 years. Local recurrences were observed in 7 ( = 31.8%) patients, metastases in 4 ( = 18.2%) and tumor-related deaths in 3. The prognosis for our patients seems to be slightly better than that described in the literature. The main reason is an improved histological diagnosis of this special type of melanoma. Using immunohistochemical staining with anti-S100 antibody it is possible to establish the melanocytic nature of these fibrotic spindle cell tumors earlier that is, in small initial biopsies, and tumor margins can be defined more accurately. As a consequence, surgery is done earlier and is more likely to be curative.