Dynamic computed tomography and Doppler findings in different subtypes of renal cell carcinoma with their histopathological correlation.

BACKGROUND: Renal cell carcinoma (RCC) is by far the most common soft-tissue mass and accounts for 85% of all malignant masses of the kidney. Histopathological subtype has clinical implications in the form of prognosis and response to various newer and adjuvant treatment strategies. AIM: The aim of this study was to evaluate the morphology and enhancement patterns of different subtypes of RCC and correlate them with their histopathological subtypes.
MATERIALS AND METHODS: The study group comprised of 20 consecutive patients of RCC. The patients were evaluated with multi-detector-row computed tomography (MDCT) and Doppler ultrasound prior to surgery and findings compared with histopathological subtypes of tumor.
RESULTS: RCC was confirmed on histopathology. Out of 20 patients with RCC, 14 were finally diagnosed as clear cell, 4 chromophobe and 2 as papillary subtypes of RCC. None of clear-cell type showed homogenous enhancement. The mean attenuation in corticomedullary phase (CMP) and nephrographic phase (NP) for clear cell and chromophobe subtype was higher than papillary subtype, i.e. 116.1 ± 27 HU and 91.9 ± 21 HU for clear cell, 103 ± 22.4 HU and 96.2 ± 9.2 HU for chromophobe subtype and 78.5 ± 12.4 HU and 73.3 ± 12.2 HU for papillary subtype respectively. On Doppler US evaluation, non-clear-cell subtypes, which showed heterogenous enhancement on MDCT showed less color flow and peak systolic velocity (PSV). The difference in PSV and Doppler shift frequency values between clear-cell carcinoma and chromophobe subtypes were statistically significant (P = 0.003).