To present our institutional experience with Smooth Muscle-Rich Renal Cell Carcinoma (smrRCC), focusing on clinical presentation, surgical management, oncologic outcomes, and genetic features.
A retrospective chart review of patients with smrRCC treated at our institution between January 2008 and April 2025 was performed.
Clinical, surgical, pathological, and genetic data were collected and analyzed.
A total of 26 patients with smrRCC were identified; the median age at initial renal surgery was 59.5 [51.5-65.3] years. The cohort included 19 (73.1%) males, 19 (73.1%) patients identified as Black/African American, and radiologically bilateral multifocal (BMF) renal masses were observed in 23 (88.5%) patients. Patients underwent 48 renal surgeries, 4 [2-6] tumors were removed per surgery, and 34 (70.8%) surgeries reported smrRCC predominant tumors only. In total, 216 tumors were resected, with 171 (79.2%) tumors demonstrating smrRCC histology. One patient with an initial smrRCC pT3 tumor (ISUP/ Furman grade 3) developed metastatic disease. We observed germline ASXL1 variants of uncertain significance in 8 (30.7%) patients.
smrRCC appears to frequently affect Black/African American individuals, although no predominant genetic alterations were identified in our cohort, smrRCC often presents with BMF disease, and patients require multiple renal surgeries. Genetic evaluations offer an intriguing possibility that germline ASXL1 gene variants might increase the risk of this tumor type. Pathology reports may reveal both smrRCC and other histologies within the same patient. Our findings suggest that pathological grade and stage may influence oncologic behavior and metastatic potential of smrRCC.
Urology. 2025 Nov 17 [Epub ahead of print]
Ruben Blachman-Braun, Milan H Patel, Braden Millan, Lauren Loebach, Cathy D Vocke, Christopher J Ricketts, Jaskirat Saini, Sandeep Gurram, Maria J Merino, W Marston Linehan, Mark W Ball
Urologic Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA., Urologic Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA. Electronic address: .
PubMed http://www.ncbi.nlm.nih.gov/pubmed/41260417