Comparative study of CT and MRI appearances in mucinous tubular and spindle cell carcinoma and papillary renal cell carcinoma.

OBJECTIVE: To explore the feasibility of CT and MRI in differentiating mucinous tubular and spindle cell carcinoma (MTSCC) and papillary renal cell carcinoma (PRCC). METHODS: 23 patients with MTSCC and 38 patients with PRCC were studied retrospectively. CT and MRI were undertaken to investigate differences in tumour characteristics. RESULTS: 23 patients with MTSCC and 38 patients with PRCC (included 15 cases Type 1,and 23 cases Type 2), tumours (mean diameter 3.7 ± 1.6 cm vs 4.6 ± 1.7 cm, p < 0.05), cystic components (5 vs 32, p < 0.01), calcifications (3 vs 11, p > 0.05), haemorrhage (1 vs 22, p < 0.01), tumour boundaries (1 vs 37, p < 0.01), and homogeneous enhancement (20 vs 11, p < 0.01). The density of MTSCC was lower than that of PRCC, normal renal cortex (p < 0.05), except for the medulla(p > 0.05). MTSCC and PRCC tumour enhancement were lower than that for normal cortex and medulla during all enhanced phases (p < 0.05). Enhancement was higher with PRCC than with MTSCC tumours during all phases (p < 0.05). On MRI, nine cases of MTSCC and 19 cases of PRCC, tumour showed homogeneous (9 vs 3, p < 0.01), heterogeneous (0 vs 16, p < 0.01), hyperintense on T1WI (0 vs 15, p < 0.01), slightly hyperintense on T2WI (9 vs 1, p < 0.01), hypointense on T2WI (0 vs 15, p < 0.05) , relatively high signal intensity was seen on DWI (9 vs 15, p > 0.05), respectively. CONCLUSION: CT imaging features of MTSCC include isodense or hypodense mass on unenhanced CT, with unclear boundaries; however, PRCC showed mild hyperdensity, easily have cystic components. The degree enhancement of MTSCC is lower than that for PRCC. On MR, MTSCC was slightly hyperintense on T2WI, whereas PRCC was hypointense. ADVANCES IN KNOWLEDGE: 1.CT imaging features of MTSCC include isodense or hypodense mass on unenhanced CT, with unclear boundaries.2. CT imaging features of PRCC include mild hyperdensity on unenhanced CT, easily have cystic components.3. On enhanced CT, the degree enhancement of MTSCC is lower than that for PRCC. On MR, MTSCC was slightly hyperintense on T2WI whereas PRCC was heterogeneously hypointense on T2WI.