Fumarate hydratase-deficient renal cell carcinoma arising in acquired cystic kidney disease in a hemodialysis patient: Diagnostic clues from percutaneous renal mass core needle biopsy: A case report.

A 76-year-old male patient with a 30-year history of dialysis presented with persistent fever and hematuria. Computed tomography and magnetic resonance imaging suggested a cyst infection associated with acquired cystic kidney disease. Although cyst drainage was planned, ultrasonography incidentally detected a solid mass within the kidney cyst, prompting a switch from drainage to percutaneous biopsy. Histopathological examination revealed fumarate hydratase-deficient renal cell carcinoma, and nephrectomy was performed. Diagnosis of dialysis-associated renal carcinoma relies on imaging techniques. However, it can be difficult to identify malignant tumors in a polycystic kidney using imaging alone, and pathological confirmation by biopsy is often required. The present report highlights the usefulness of performing needle biopsy for suspected masses using the same method that is used by nephrologists for kidney biopsy in cases in which determining the lesion nature from imaging alone is difficult and in hydratase-deficient renal cell carcinoma arising in acquired cystic kidney disease as a dialysis-associated renal carcinoma.