Multiple Discordant Histology after Nephrectomy: Descriptive Analysis and Outcomes

Background While RCC is the most common primary renal neoplasm, few cases of ipsilateral renal lesions of different RCC histologic subtypes have been described. The objective of this study was to evaluate our experience with synchronous, histologically unique, primary renal neoplasms within the same kidney. Patients and Methods We retrospectively analyzed 2 institutional nephrectomy databases from 2000 to 2013. The study cohort comprised 15 patients with multiple, discordant renal histology after partial or radical nephrectomy. Demographic data, immunohistochemical analysis, and clinical course were assessed and analyzed. Results Eight patients (53%) were black, 10 (60%) were male, and 5 (36%) were tobacco users. Median follow-up time was 13 months (range, 1-62 months), and 9 patients (56%) underwent radical nephrectomy. Among 36 tumors, the median tumor size was 2.3 cm (range, 0.4-9 cm). The most common combination of discordant tumor histology among patients with ≥ 2 tumors was clear-cell (cc) renal-cell carcinoma (RCC) with chromophobe RCC (3 cases, 19%). In 3 patients (19%), a single tumor was noted to have 2 distinct patterns; all patients had ccRCC with papillary RCC. Three (20%) of 15 patients developed metastatic disease. The median cancer-free survival time for patients with metastasis was 2 months. Conclusion Multiple, discordant renal pathology represents a rarely reported entity in patients receiving nephrectomy. We introduce the largest cohort of synchronous renal tumors, of which ccRCC/chromophobe RCC was the most common pairing.