Case Report: The Natural History of Untreated Sarcomatoid Renal Cell Carcinoma: An Autopsy Report

Objective: To report a case of an autopsy that disclosed an untreated sarcomatoid renal cell carcinoma (RCC) with a 9-year natural history. Clinical Presentation and Intervention: An 86-year-old woman presented with acute cystitis. Ultrasonography revealed an incidental left renal mass measuring 2 × 3 cm. After 8.9 years, multiple liver metastases were detected on ultrasound. After 9.0 years, the tumor had increased by 3.5 cm from the initial size, and multiple lung metastases were also detected. After 9.1 years, the patient developed multiple metastases and died from progressive disease at the age of 95. On autopsy, metastases were found in both lungs, bilateral hilar lymph nodes of the lung, the liver, both adrenal glands and the bone marrow. Conclusion: This case showed a probable slow transition from typical RCC to sarcomatous elements that remained untreated for 9 years before the patient died.