The Specific Magnetic Resonance Imaging Indicators in Predicting Clear-Cell Renal Cell Carcinoma Metastatic to the Sinonasal Region

PURPOSE: The aim of this study was to determine the valuable magnetic resonance imaging (MRI) features of sinonasal metastatic clear-cell renal cell carcinoma (cc-RCC), especially focusing on its dynamic-enhanced characteristics. METHODS: The conventional and dynamic-enhanced MRI findings of 8 patients with histopathologically confirmed sinonasal metastatic cc-RCC were reviewed by 2 radiologists. The control group of 8 patients with capillary hemangioma underwent the same MRI protocol. RESULTS: Metastatic cc-RCCs arose from the nasoethmoid region, maxillary sinus, posterior ethmoid and sphenoid sinus, and nasal cavity in 2 patients in each. These lesions were well circumscribed and the mean maximum dimension was 42 mm. The signal intensity of these lesions was isointense to brain stem on both MR T1- and T2-weighted images. All metastatic tumors showed vivid enhancement on enhanced T1-weighted image. Multiple flow voids within these metastatic lesions were identified in 6 patients. Peripheral cyst was detected around the metastatic tumor in 4 patients. Metastatic cc-RCCs exhibited a characteristic type 4 time intensity curve (TIC) similar to that of the internal carotid artery, whereas capillary hemangiomas showed a type 3 TIC on dynamic-enhanced MRI. CONCLUSIONS: A hypervascular mass with the characteristic type 4 TIC in the sinonasal region is highly suggestive of a metastatic cc-RCC.