MICROCYSTIC ADNEXAL CARCINOMA

A 55-year-old man presented with an ulcer on the right sole present fo r 8 years. The ulcer measured 6.5 x 3 cm and affected the entire dista l sole of the right foot; the margins were everted and an intermittent serosanguineous discharge was present. The general condition of the p atient was good, with findings limited to the ulcerated lesion. There was no history of hypertension, diabetes mellitus, or venous stasis. A biopsy taken from the ulcer edge was interpreted as squamous cell car cinoma, Grade I. A transmetatarsal amputation was carried out and the specimen sent for histopathologic examination. Histologically, the epi dermis showed ulcerated areas; adjacent areas showed hyperkeratosis an d irregular acanthosis. Keratin cysts containing well-developed lamell ar keratin were present in the upper dermis (Fig. 1). Nests and strand s of squamous and basaloid cells, having scanty eosinophilic cytoplasm , alternated with the cysts. Areas of ductular differentiation were al so noted. The epithelial strands were separated by concentric bands of moderately cellular fibrous tissue in the upper and mid-dermis. In th e deeper areas of the tumor the epithelial nests became progressively smaller in size, diminishing to small clusters of two or three cells, and were surrounded by a sclerotic stroma. Cytologic atypia was minima l and no significant mitotic figures were identified. The neoplasm sho wed extensive infiltration of subcutaneous fat and striated muscle wit h frequent perineural involvement in the deeper parts. There was no ex tension to bone or perichondrium. Immunoperoxidase staining carried ou t for carcinoembryonic antigen (CEA) showed positivity in the lumina a nd lining cells of the ducts (Fig. 2). Based upon the classical micros copic appearance, a diagnosis of microcystic adnexal carcinoma was mad e. The patient has been followed for a period of 3 years with no evide nce of tumor recurrence.