Adenocarcinoma of the bladder following nephrogenic adenoma: a case report

INTRODUCTION: Nephrogenic adenomas are generally considered to be benign lesions, but there remains a risk for malignant transformation. Patients with immunosuppression in particular appear to be at a higher risk of malignant disease. We report a case of post-traumatic nephrogenic adenoma in a young patient without immunosuppression, which transformed into an adenocarcinoma of the bladder. CASE PRESENTATION: A 25-year-old man had a traumatic bladder perforation caused by a car accident. After physical recovery from the accident, he developed a neurogenic bladder and recurrent urinary tract infections. He presented with nephrogenic adenoma of the bladder 18 months after the accident. The adenoma was treated repeatedly with transurethral resections. The initial pathologic findings were benign, however, the last resection revealed that the former benign adenoma had transformed into a moderately differentiated adenocarcinoma of the bladder (tumor present but no invasion, multifocal, no lymph nodes involved, no metastasis, grade 2). He subsequently underwent radical cystectomy and has remained tumor-free for the last 4 years. CONCLUSION: Nephrogenic adenoma is a rare disease with some potential for malignant transformation. However, patients with nephrogenic adenoma under immunosuppression and patients with neurogenic bladder dysfunction appear to be at a higher risk of developing bladder cancer.