Radiological differentiation of succinate dehydrogenase–deficient renal cell carcinoma from renal oncocytoma and chromophobe renal cell carcinoma

PURPOSE: To characterize the imaging features of succinate dehydrogenase-deficient renal cell carcinoma (SDH-RCC) and compare them with those of renal oncocytoma (RO) and chromophobe RCC (chRCC). METHODS: This retrospective two-center study was approved by the institutional review board, and informed consent was waived. Patients with histologically confirmed SDH-RCC, RO, or chRCC who underwent pre-treatment contrast-enhanced CT between November 2015 and October 2024 were included. Imaging features were independently evaluated by two abdominal radiologists, with consensus in case of disagreement. Tumor size, location, margins, calcification, invasion, lymphadenopathy, distant metastases, and contrast enhancement parameters were analyzed and compared among groups. RESULTS: A total of 45 patients were enrolled, including 9 with SDH-RCC, 18 with RO and 18 with chRCC. SDH-RCC presented as relatively small (mean size, 3.4 cm), solitary masses without calcification, vascular invasion, or metastasis. Ill-defined margins were observed in 22.2% of SDH-RCC but rarely in the other groups (p = 0.015). The relative enhancement ratio in the corticomedullary phase differed significantly, with RO showing the highest values with 0.76 (p = 0.046). No significant differences were noted in the nephrographic or delayed phases. Among the SDH-RCC patients who underwent contrast MRI, two cases (66.7%, 2/3) demonstrated hemorrhagic features, which was another significant imaging sign that differed from RO and chRCC (p < 0.001). CONCLUSION: SDH-RCC exhibits imaging features that partially overlap with RO and chRCC but also demonstrates distinctive characteristics, particularly ill-defined margins and hemorrhagic features. Awareness of these findings, integrated with clinical and genetic context, may assist radiologists in raising suspicion for SDH-RCC.