AIM: Little information has been reported with regard to the radiological features of chromophobe cell renal carcinomas (CCRC). The aim of the present study was to identify imaging characteristics which lead to the histological diagnosis of CCRC. METHODS: The imaging findings of computed tomography (CT) and magnetic resonance imaging (MRI) were retrospectively analyzed in 11 patients with CCRC operated on at Tokyo Women's Medical University, Tokyo, Japan. RESULTS: None of the factors studied were significant in distinguishing the two variants, typical and eosinophilic variants. Enhanced CT scans showed a spoke-wheel-like enhancement with a central scar in 3 patients (27%). The radiological patterns were classified into two groups. Seven patients (64%) showed pattern 1 in which: (i) a hypodense to isodense enhancement compared to the renal medulla in the corticomedullary phase during dynamic CT; (ii) an isodense mass compared to the renal medulla in unenhanced CT scan; and (iii) a lobulated appearance were typically observed. Four patients (36%) showed pattern 2 that seemed to be similar to the features of clear cell carcinoma, having an alveolar structure including a hyperdense enhancement in the corticomedullary phase and an inhomogeneous appearance. A spoke-wheel-like enhancement was observed only in patients with pattern 1, and was more clearly demonstrated in larger tumors. CONCLUSIONS: The CT and MRI findings in CCRC patients were not uniform, but it was noted that a spoke-wheel-like enhancement with a central stellate scar, which might have been mistaken for oncocytoma, was one of important findings of CCRC. Tumors demonstrating a spoke-wheel-like enhancement with a central scar should be carefully managed, because they could be malignant.
AIM: Little information has been reported with regard to the radiological features of chromophobe cell renal carcinomas (CCRC). The aim of the present study was to identify imaging characteristics which lead to the histological diagnosis of CCRC. METHODS: The imaging findings of computed tomography (CT) and magnetic resonance imaging (MRI) were retrospectively analyzed in 11 patients with CCRC operated on at Tokyo Women's Medical University, Tokyo, Japan. RESULTS: None of the factors studied were significant in distinguishing the two variants, typical and eosinophilic variants. Enhanced CT scans showed a spoke-wheel-like enhancement with a central scar in 3 patients (27%). The radiological patterns were classified into two groups. Seven patients (64%) showed pattern 1 in which: (i) a hypodense to isodense enhancement compared to the renal medulla in the corticomedullary phase during dynamic CT; (ii) an isodense mass compared to the renal medulla in unenhanced CT scan; and (iii) a lobulated appearance were typically observed. Four patients (36%) showed pattern 2 that seemed to be similar to the features of clear cell carcinoma, having an alveolar structure including a hyperdense enhancement in the corticomedullary phase and an inhomogeneous appearance. A spoke-wheel-like enhancement was observed only in patients with pattern 1, and was more clearly demonstrated in larger tumors. CONCLUSIONS: The CT and MRI findings in CCRC patients were not uniform, but it was noted that a spoke-wheel-like enhancement with a central stellate scar, which might have been mistaken for oncocytoma, was one of important findings of CCRC. Tumors demonstrating a spoke-wheel-like enhancement with a central scar should be carefully managed, because they could be malignant.