Dermatofibrosarcoma protuberans and basal cell carcinoma.

A 70-year-old male presented with an asymptomatic slowly growing brownish nodular lesion involving the left ear. The patient had noticed a rapid growth of the lesion in the previous 3 months. A biopsy followed by wide excision was performed. The biopsy consisted of a piece of skin measuring 1 cm with a firm dermal lesion. Microscopic examination showed a skin with basal cell carcinoma (Fig. 1) and a cellular dermal lesion. The lesion is composed of relatively uniform spindle-shaped cells arranged in a distinctive cartwheel or storiform pattern. Mitosis was infrequent. The tumour cells were positive for vimentin and CD34 (Signet Laboratories Inc) and negative Fig. 1. Basal cell carcinoma overlying dermatofibrosarcoma profor cytokeratin epithelial membrane antigen S100, actin and desmin tuberans (arrow). (Dako). Their appearance indicated a diagnosis of a DFSP and basal cell carcinoma. Further resection revealed a residual cellular tumour with similar appearance involving the subcutaneous tissue. A multitude of epidermal changes are commonly associated with dermatofibromas, and very rarely with DFSP. These include epidermal acanthosis, occasional pseudoepitheliomatDISCUSSION ous hyperplasia, hair follicle proliferation, and basal cell DFSP, first described in 1924 as ‘‘a progressive and recurrent carcinoma-like changes. A few cases of well-documented basal dermatofibroma’’, is a nodular cutaneous tumour charactercell carcinoma have been reported (3). The most likely explanaized by a distinctive storiform growth pattern and local tion for this coexistence of DFSP and basal cell carcinoma recurrence. It is generally regarded as a neoplasm of interis incidental, as the latter commonly occurs on sun-exposed mediate malignancy with rare distant metastasis. DFSP typicskin. ally arises on the trunk and proximal extremities. Head, neck and scalp lesions have also been described. It is more frequent in men, with a peak incidence during the third decade of REFERENCES life (1). The tumour usually develops as a nodular or multinodular, 1. Conelly JH, Evans HL. Dermatofibrosarcoma Protuberans: a clinicslowly growing cutaneous mass and appears to evolve from a opathologic review with emphasis on fibrosarcomatous area. Am dermal fibrous plaque stage. Local recurrence after simple J Surg Pathol 1992; 16: 921–925. excision occurs in 30% of cases. Metastases usually occur after 2. McLelland J, Chu T. Dermatofibrosarcoma protuberans arising in repeated recurrence, often with fibrosarcomatous transformaBCG vaccination scar. Arch Derm 1988; 124: 496. 3. Goeffe LTC, Helvig EB. Basal cell carcinomas and basal cell tion and, because of this and high recurrence rate, wide carcinoma-like changes overlying dermatofibromas. Arch Derm excision is advised. 1975; 111: 589–599. Histogenesis of the DFSP is controversial. Fibroblastic, histiocytic or perineural cells have been suggested as the cell of derivation. DFSP is considered to have no precipitating Accepted November 24, 1997. cause and in most case reports no comment is made of possible etiological factors. A history of prior trauma is usually menK. Ibrahiem and J. M. Radhi tioned following BCG vaccination and ionizing radiation for Department of Pathology, Royal University Hospital, 107 Hospital Drive, Saskatoon, Saskatchewan, S7N 0W8, Canada. basal cell carcinoma (2).