A fusiform nodule on the flank

An otherwise healthy 61-year-old female presented with a skin tumor on the left flank, which had been present since her early adulthood. The tumor gradually enlarged during the first 2–3 years and then stabilized in size. There were no symptoms from the tumor. On examination, a red to violaceous, shiny, polypoid, fusiform nodule with firm consis tency, measuring approximately 3.0 cm × 2.0 cm, was noted on her left flank (Figure 1). There were also many skin tumors on her face and scalp, most of which were dome-shaped, smooth surfaced, violaceous, firm nodules measuring several millimeters in diameter. These tumors were 1-cm dermal nodules that caused pain; others were rounded, skin-colored, firm papules with a size of approximately 5 mm in diameter around her nose. An excisional biopsy specimen was obtained from the tumor at the flank. Histopathologic examination revealed a tumor occupying the reticular dermis, which was composed of aggregations of neoplastic cells arranged in a jigsaw puzzle pattern. The aggregations consisted of neoplastic cells with two different appearances: (1) peripheral cells aligned in a palisade with small, dark staining columnar nuclei surrounded by a scant cytoplasm, and (2) cells with nuclei that were larger and paler, and that had a more abundant pale cytoplasm. Each aggregation was surrounded by a rim of homogenous eosinophilic basement membrane-like material. Globules of the same material were also present within the aggregations themselves (Figure 2). The patient then underwent several sessions of surgical removal for other tumors on the face and scalp, and pathology exams showed cylindroma, spiradenoma, trichoepithelioma, or combinations of them (Figure 3A: cylindroma + trichoepithelioma; Figure 3B: cylindroma + spiradenoma). She reported that two of her younger brothers and sisters also had similar skin tumors, but they were not as numerous as hers.