No abstract

Case reportA 71-year-old Caucasian woman presented with a 4-year history of an asymptomatic nodule within the left labia majus. A firm, irregular, 3 cm dermal lesion was noted, with an overlying area of macular hyperpigmentation. The nodule was non-tender and there were no other similar lesions at other body sites. A clinical diagnosis of an epidermoid cyst was made and excision biopsy undertaken. Histology revealed a dermal tumour consisting of large cells with a granular eosinophilic cytoplasm and small, bland, round or oval nuclei. Marked overlying pseudoepitheliomatous hyperplasia was noted. No cytological atypia or mitoses were seen in the dermal infiltrate. Immunohistochemistry showed the cytoplasmic granules to be S100 and D-PAS positive, and nuclear S100 positivity was also noted (Figure 1). Small groups of tumour cells were noted to infiltrate deeply into the dermis, and the tumour was reported to be incompletely excised.

We present a case of a 50-year-old man with unusual extensive linear lesions on the right leg that had been present from the age of 2 years. As a child he had been treated with oral steroids under a working diagnosis of linear scleroderma. He went on to undergo multiple operations and skin-grafting procedures under the care of the plastic surgeons and presented to the dermatology department in 2004 because of itchy, scaly and painful lesions extending from the original area. Multiple biopsies had been taken, all showing similar histopathological features of a poorly differentiated dermal lesion composed of fibrohistiocytic cells arranged in a whorled pattern, similar to that seen in dermatofibroma. There was positive staining with vimentin and SMA, and negative staining with caldesmon, D33, CD34, S100 and factor 13a, indicating that the cell of origin was a myofibroblast. Clinically this extensive lesion does not fit the characteristics of a dermatofibroma. It also does not fit readily into any previously described fibrous tissue tumour condition, and, to our knowledge, is a unique case. The patient remains under close clinical observation given that there is no way of predicting the long-term prognosis, but to date no suspicious features have been seen.