Secondary neoplasms of the urinary system and male genital organs.

BACKGROUND AND AIMS: In this review we discuss those secondary tumours involving the urinary system and male genital organs that can pose differential diagnostic difficulties with primary lesions, and highlight morphological and ancillary features that could be helpful in reaching a proper assignment of primary origin. MATERIALS AND METHODS: Based on MEDLINE database searches all reports of secondary tumours involving the urinary system (kidney and bladder) and male genital organs (prostate, testis and penis) were examined. RESULTS AND DISCUSSION: Involvement by a secondary tumour occurs either as a metastasis or by direct extension. Among non-genitourinary primary sites, colorectal, pulmonary, skin (melanoma) and breast are the most common contributors. Secondary spread from a genitourinary site primary tumour to another genitourinary organ occurs most frequently between the prostate and urinary bladder, given the intimate topographic proximity of the two. The prognosis is very poor, as the secondary tumour usually occurs in patients with carcinoma in the late stages. Few secondary tumours have distinctive histological and immunohistochemical features, making it difficult to make the appropriate diagnosis. Hence, knowledge of the history and clinical setting are particularly important in these cases. CONCLUSION: The urinary system and male genital organs are not common sites for secondary tumours. They often go either undiagnosed or misdiagnosed in the clinical follow-up of patients with cancer. Accurate diagnosis is essential because of differing therapeutic approaches compared with a primary neoplasm.