Bilateral multifocal renal neuroendocrine carcinoma with synchronous pancreatic neuroendocrine carcinoma and adrenal lesion.

Renal neuroendocrine neoplasms are exceptionally rare and may mimic renal cell carcinoma on imaging. A 48-year-old man presented with one week of left flank pain. Ultrasound showed bilateral renal masses with a left subcapsular hematoma. Computed tomography and magnetic resonance imaging demonstrated multiple solid lesions in both kidneys with marked diffusion restriction, accompanied by a pancreatic uncinate mass, a right adrenal lesion, renal hilar lymphadenopathy, and a right retroperitoneal nodule. The patient underwent left nephrectomy and pancreatic biopsy. Histopathology confirmed neuroendocrine carcinoma involving the kidney and pancreas with nodal metastasis. This unusual constellation should prompt consideration of an underlying tumor predisposition syndrome such as von Hippel-Lindau disease, with recommendation for genetic counseling/testing and multidisciplinary surveillance. The patient improved after post-biopsy pancreatitis with conservative management and was referred for multidisciplinary oncologic management and imaging follow-up.