A rare case of epidermoid cyst of the scrotum with signs of malignization--clinical and morphological features.

Proceeding from the fact that epidermoid cysts of the scrotum are rare and often histologically proven to display evidence of malignization in the underlining epithelium, the authors present a case of scrotal epidermoid cyst from their clinical practice. Epidermoid cysts are given a detailed pathohistologic assessment. The finding was a productive granulomatous inflammation containing multinucleated giant cells of foreign body type in the overlying dermis and intraepidermal "horn pearls" (keratin substance of Queyrat) showing unequivocally signs of malignization of the epidermoid cyst. The authors argue that a histological study should be a must after surgical removal of the cyst as it is the only method to prove beyond any doubt the malignant transformation of the epithelium.