Malignant rhabdoid tumor of the kidney in a 27-Year-Old adult: a rare case with favorable outcomes following surgery and adjuvant radiotherapy

Malignant rhabdoid tumors of the kidney are exceptionally rare in adults and typically occur in children under 2 years of age. This case report outlines the diagnosis, treatment, and outcome of an adult patient with renal malignant rhabdoid tumors. A 27-year-old man presented with febrile urinary tract infection and reported intermittent hematuria for six months. Imaging revealed a left renal mass initially misdiagnosed as an abscess. Tumor progression was later confirmed, and biopsy identified an malignant rhabdoid tumors, characterized by the loss of INI-1 nuclear protein expression and homozygous deletion of the SMARCB1 gene. Radical nephrectomy was performed, followed by adjuvant radiotherapy (36 Gy in 20 fractions), on the basis of pediatric protocols. The tumor was staged as pT3a N0 R0, with no extrarenal extension or metastases. No significant radiotherapy-related toxicity was observed. After five years of follow-up with alternating CT and MRI, the patient remained free of recurrence or metastasis. Postoperative renal function was stable despite the nephrectomy and radiotherapy. This case adds to the limited number of reported adult renal malignant rhabdoid tumors. Early diagnosis, complete surgical resection, and adjuvant radiotherapy may contribute to long-term remission. Pediatric treatment guidelines may be valuable in managing these rare adult cases.