Penile clear cell carcinoma: a report of 5 cases of a distinct entity

We present a series of 5 penile clear cell carcinomas, which arose in middle-aged men at the inner side of the foreskin. They were large, exophytic, partly ulcerated, and widely invasive tumors with sharp demarcation to the surrounding normal skin/mucosa. Histologically, they were composed of large clear cells with intracytoplasmic PAS/d-PAS-positive material and showed extensive lymphatic and blood vessel invasion. Strong staining with antibodies to Muc-1, EMA, and CEA was typical. All carcinomas harbored HPV16 DNA, although only one carcinoma revealed HPV-related cytologic cell changes. All 5 patients had extensive, partly cystic inguinal lymph node metastases with a striking clear cell differentiation and focal dense sclerotic basement membrane material, either at or within several months after initial diagnosis. Two patients are alive without disease after 7 and 10 years. One patient died after 9 months of widespread disease and 2 patients are presently alive at 7 and 17 months follow-up with widespread lymphatic and hematogenous metastases despite adjuvant chemo- and radiation therapy. In contrast to squamous cell carcinoma, penile clear cell carcinomas show extensive blood and lymph vessel invasion and early metastases to regional lymph nodes. Clear cell carcinomas represent a distinct group of penile cancers that may have a different clinical behavior than usual penile squamous cell carcinomas.