Giant Hidroacanthoma Simplex Combined with Variable Eccrine Tumors Mimicking Clonal Seborrheic Keratosis / 대한피부과학회지

ABSTRACT

Hidroacanthoma simplex (HAS) is a rare benign intraepidermal neoplasm arising from the eccrine duct. Histologically, HAS exhibits the “Borst-Jadassohn phenomenon” and consists of intraepidermal cell nests, which resemble the features of clonal seborrheic keratosis. An 86-year-old woman presented a more than 10-year history of a 7.5 cm×5.6-cm brown verrucous plaque on her right pelvis. Histopathological examination showed intraepidermal clonal cell expansion of polygonal basaloid cells. The lesions were removed by CO2 laser, but polypoid papules recurred after 3 months. Histologic examination showed proliferation of polygonal basaloid cells with atypia and frequent mitosis. In addition, findings suggestive of syringofibroadenoma were observed. The tumor cells were positive for epithelial membrane antigen (EMA) and periodic acid-Schiff (PAS) staining. Based on these findings, we diagnosed the patient with HAS combined with variable eccrine tumors. Herein, we report a case of giant HAS combined with variable eccrine tumors showing a natural progression of eccrine tumors from HAS to eccrine porocarcinoma in situ.