A 71-year-old man presented with an erythematous plaque around the urinary meatus that had been slowly enlarging for the past eight months. Six months before presentation, the patient was treated based on an impression of eczema. He had a history of radical cystectomy with ileal conduit urinary diversion for urothelial carcinoma of the bladder three years previously. The resected margin was negative and no recurrence had been detected afterward. Physical examination revealed a scaly, erythematous plaque around the urethral orifice (Fig. 1).
Histopathology demonstrated an intraepidermal proliferation of large cells in a pagetoid pattern (Fig. 2A). Immunohistochemical stains were positive for CAM5.2 and CK7, consistent with extramammary Paget’s disease (EMPD). Further stains were positive for both CK20 and p63, revealing a high risk of secondary EMPD (Fig. 2B)1. Based on the clinical history, secondary EMPD with underlying urothelial carcinoma was diagnosed.
A preoperative magnetic resonance imaging of the pelvic area revealed no remarkable findings other than lesion enhancement on the glans penis. The patient underwent partial penectomy and urethrectomy. Histopathologic findings showed urothelial carcinoma in situ (pTis) on the urethra spreading to the penile skin and that the surgical margins were free. There was no evidence of recurrence at 10 months postoperatively, and the patient continues to undergo regular check-up.
EMPD is mostly not associated with an underlying malignancy, but a 20% to 30% risk has been reported for secondary EMPD2. While primary EMPD arise from the apocrine glands or pluripotent cells in the epidermis, secondary EMPD originate from an internal malignancy or an underlying adnexal carcinoma2. Common underlying malignancies include carcinomas of the colon, rectum, bladder, urethra, cervix, and prostate2. Associations between the affected area and the origin of malignancy have been reported. EMPD of the perianal area may be related to colorectal cancer and cases in the external genitalia may be associated with malignancies of the bladder and urethra2. Workup should focus on the possibility of the underlying malignancy2. This patient have had regular age appropriate cancer screening including chest radiography and colonoscopy without any abnormal findings after initial surgery. Thus, the most likely diagnosis was EMPD secondary to urothelial carcinoma.
Clinical presentation of EMPD can be nonspecific, which can lead to a misdiagnosis such as candidiasis, tinea cruris, inverse psoriasis, contact dermatitis, and intertrigo, resulting in an average delay in diagnosis of two years3. On the penile area, Bowen’s disease, Zoon’s balanitis, and erythroplasia of Queyrat should be ruled out4. To facilitate timely diagnosis, an early biopsy is recommended for persistent, erythematous lesion in the anogenital and axillary area3.
Surgery is the standard treatment and additional management of the underlying cancer should be performed in secondary EMPD5. Other options, namely radiotherapy, chemotherapy, and photodynamic therapy, are beneficial for poor surgical candidate or as an adjuvant therapy2. The prognosis for secondary EMPD is worse than primary EMPD and associated with the underlying malignancy2.
When recalcitrant, eczematous lesion occurs on the glans penis, it should be checked for genitourinary carcinoma and EMPD should be considered in the differential diagnosis.