Abdominal seeding of renal cell carcinoma: radiologic, pathologic, and prognostic features

Purpose: We analyzed radiologic and histologic characteristics, and prognosis of abdominal seeding from renal cell carcinoma (RCC). Methods: Consecutive 25 patients with RCC and histologically or radiologically diagnosed abdominal seeding were analyzed. No patient had another type of malignancy. Histologic subtype, Fuhrman grade, sarcomatoid differentiation, and T-stage of primary tumors were assessed. Pre- or postoperative presentation of seeding was investigated. Median survival time and RCC-specific survival rates were evaluated. Results: Of 25 patients, 15 (60%) died and 4 (16%) were hopelessly discharged (median follow-up time, 6 months; range 1–62 months). Histologic subtypes were clear cell (76%, 19/25), papillary (16%, 4/25), chromophobe (4%, 1/25), and poorly differentiated (4%, 1/25). Fuhrman grades were 4 (48%, 12/25), 3 (36%, 9/25), 2 (12%, 3/25), and unknown (4%, 1/25). T-stage of the four patients with grade 2 or unknown was 3a. Sarcomatoid differentiation and postoperative occurrence were found in 32% (8/25) and 80% (20/25), respectively. Median survival time was 13 months, and 1-year, 2-year, and 3-year RCC-specific survival rates were 51%, 41%, and 31%, respectively. Conclusion: Abdominal seeding may occur in various subtypes of RCC with high Fuhrman grade including sarcomatoid differentiation or high T-stage, and appears to be related to poor prognosis.