A 66-year-old male presented with a pruritic, 3×2 cmsized, erythematous brownish solitary plaque with crusted and verrucous surface on the extensor surface of the right thigh (). The lesion developed 6 to 7 years ago, and had been growing slowly. There was no palpable inguinal lymph node enlargement, and the patient had been otherwise healthy. Biopsy revealed epithelial strands extending down to the dermis, forming anastomoses (). Epithelial strands were composed of 2 areas: the upper area consisting of dysplastic cells with prominent nucleoli and abundant mitoses, and the lower area consisting of oval and round cells, and occasionally small luminal ducts (). Dysplastic cells comprised almost the entire epidermis but did not invade into the dermis (). There was a sharp contrast and demarcation between the upper dysplastic lesion and the benign adenomatous lesion immediately surrounding the dysplastic keratinocytes in the lowermost portion of the epidermis (). In immunohistochemical stains, epithelial membrane antigen (EMA) was positive in the dysplastic cells and weakly positive in the ductal structures in the adenomatous lower portion (). p63 was more intensely positive in the dysplastic cells than in the adenomatous cells (). Carcinoembryonic antigen (CEA) stain was weakly positive in the ductal structures in the adenomatous lower portion (). The lesion was diagnosed as a reactive ESFA associated with Bowen's disease and was completely excised with free margins of the tumor. Histopathology of excised tissues was also consistent with reactive ESFA associated with Bowen's disease ().
A 90-year-old Japanese woman presented with a 4-year history of hyperkeratotic lesions on her left heel that had not been improved by topical treatment with salicylic acid petrolatum ointment or 10% urea cream. There was no history of trauma, but she gradually found it hard to walk because of her left heel pain. The patient had been taking clopidogrel, aspirin, azosemide, metformin hydrochloride, and alogliptin benzoate for the treatment of chronic heart failure, angina, and diabetes mellitus, and all of these symptoms had been well controlled. At the first visit, a clinical examination revealed an erythematous plaque with multiple brown macules, ulcer, and hyperkeratosis ().\nDermoscopy demonstrated glomerular vessels with regular arrangement in the ulcer area () and red-black homogeneous areas in the erythematous area (). She had no particular family history. Although we recommended that she undergo a skin biopsy to diagnose the skin lesion, the patient and her family expressed a strong desire to treat the lesion through a single surgical operation because she was at an advanced age, and the possibility of squamous cell carcinoma could not be completely excluded. Therefore, the skin lesion was totally excised.\nThe histopathological examination revealed hyperkeratosis and thin anastomosing strands of cuboidal cells extending from the epidermis to the upper dermis (). Small ductal structures and cystic changes were observed within the interconnected strands of cells. Hematomas were found in the intracorneal region and upper dermis (). No mitotic or dysplastic cells were observed. The cells of the ductal and cystic structures were positive for carcinoembryonic antigen (CEA) (Figures and ). Based on these findings, the lesion was diagnosed as a reactive ESFA.