Extramammary Paget Disease of Peristomal Skin Secondary to Bladder Urothelial Carcinoma

Abstract

Check for updatesperistomal rash for many years. The patient reported the rash had been present for at least 5 years and was getting larger. It was described as pruritic and tender. The rash was initially attributed to urine leakage and had been treated as eczema, a fungal infection, and with wound and stoma care unsuccessfully for years before presentation. Patient had been using wound cleanser spray, normal saline, nystatin powder, and miconazole. The dermatologic exam revealed a large erythematous plaque with areas of maceration around the stoma involving most of the right abdomen extending to the pubis (Figure 1a and Figure 1b). A shave biopsy was performed from around the peristomal lesion for histopathologic diagnosis. The biopsy showed infiltration of the epidermis with large, atypical epithelioid cells with enlarged hyperchromatic nuclei and pale cytoplasm in solitary units and nests (Figure 2a and Figure 2b). These cells showed diffuse and strong expression of CK7 (Figure 2c) and GATA 3 (Figure 2d), and focal expression of CK20, CDX2, and BerEp4. The cells were negative for P63, CEA, Sox10, PSA, and TTF-1. No intracytoplasmic mucin was seen on mucicarmine stain and periodic acid-schiff stain was negative for fungal organisms. The morphologic and immunohistochemical features are consistent with secondary extramammary Paget Disease, consistent with involvement by the patient's known urothelial carcinoma of the bladder.