More than skin deep: Paget's disease of the perineum.

Hong Kong Med J ⎥ Volume 20 Number 3 ⎥ June 2014 ⎥ www.hkmj.org In July 2012, an extensive eczematous lesion was found incidentally over the external genitalia in a 77-year-old man who was being evaluated for lower limb cellulitis. The affected area had been present for 10 years; it was erythematous, macerated, and itchy. He had consulted countless doctors, but the itchiness was intense and the area of involvement was enlarging despite application of topical creams. On physical examination, the perineum was weepy with excoriation, crusts, and a serous discharge. The erythematous skin was indurated and had a well-defined margin. The penis shaft was swollen with palpable groin lymph nodes (Fig 1). Blood tests showed eosinophilia (1.1 x 109 /L) and an elevated erythrocyte sedimentation rate (58 mm/h). A clinical suspicion of extramammary Paget’s disease (EMPD) was suggested by the dermatologist. Skin biopsy of the right suprapubic region confirmed the diagnosis (Fig 2), while another biopsy of the left groin showed poorly differentiated invasive carcinoma, consistent with invasive EMPD. Urine for cytology, as part of the malignancy screening, showed atypical cells. Computed tomography of the abdomen revealed left ureteric obstruction with enhanced mural thickening of left ureter, of which transitional cell carcinoma could not be excluded. He was referred to a urologist for further assessment. Radiotherapy to the affected skin lesions was given in view of the extensive involvement. Extramammary Paget’s disease is a rare intraepithelial adenocarcinoma of the skin rich in apocrine glands, first described by Crocker in 1888.1 The disease involves the epidermis, but can potentially metastasise via the lymphatic system.2 Its clinical and histological features are similar to Paget’s disease of the nipple. The penis, scrotum, and vulva are frequently involved in sites. The erythematous area has a sharp margin and scaly surface. Intense itchiness is common and may result in erosion, excoriation, and lichenification.2