Paget's disease of the glans penis secondary to transitional cell carcinoma of the bladder: a report of two cases and review of the literature

Background:  Extramammary Paget's disease of the glans penis secondary to transitional cell carcinoma (TCC) of the bladder is rare, with only a few cases reported in the literature. We report two new cases, one detected before diagnosing bladder TCC. Methods:  We describe the clinicopathologic features of two patients with intraepithelial spread of glans TCC and the histochemical and immunohistochemical features of the neoplasm. Results:  Light microscopy detected intraepithelial proliferation of neoplastic, large, pale cells located predominantly in the basal and parabasal layers of the epithelium. The pagetoid cells showed positive cytoplasmic staining for mucosubstances and immunoreactivity for CK20. The previously reported cases are reviewed and the differential diagnosis is discussed. Conclusions:  As many benign and malignant glans lesions may be clinically similar, histologic study is necessary to correctly diagnose primary lesions and promptly detect underlying asymptomatic visceral malignancies initially presenting as Paget's disease.