Eccrine Poroma with Concurrent Basal Cell Carcinoma: A Rare Combination

Eccrine poroma (EP) is a benign skin appendicular tumor that differentiates into the terminal sweat duct and is often differentiated from basal cell carcinoma (BCC) and seborrheic keratosis. This report describes a 58-year-old woman who presented with left occipital plaque. Histopathological analysis showed that the tumor cells were located in the lower part of the epidermis. The tumor cells were cuboidal or circular basal-like cells of the same size. The surrounding cells were not arranged in a palisade shape. Scattered tumor clusters composed of basal-like cells were also seen in the dermis, staining basophilic, and the surrounding cells were arranged in a palisade pattern. Immunohistochemistry showed that BerEP4, epithelial membrane antigen EMA, carcinoembryonic antigen CEA, Bcl-2, CD10, CK7 were positive, AR, PAS were negative. According to the pathological examination and immunohistochemical results, a case of eccrine poroma with concurrent basal cell carcinoma was diagnosed.