Small (clear cell renal cell carcinoma: correlation between CT findings and histologic grade

PURPOSE - To evaluate the correlation between CT findings and histologic grade of small clear cell renal cell carcinoma (ccRCC).

METHODS - CT scans of 101 patients with small ccRCC were reviewed independently by two radiologists for tumor size, shape, margin, encapsulation, enhancement pattern, and visual relative enhancement.

Enhancement patterns were defined according to the percentage of uniform enhancement [pattern 1, homogeneous (≥90%); pattern 2, relatively homogeneous (≥75 and <90%); and pattern 3, heterogeneous (<75%)]. Quantitative parameters representing attenuation and degree of enhancement were calculated. Histologic grade was classified as low (Fuhrman grade I or II) and high (Fuhrman grade III or IV). CT imaging variables were analyzed using univariate and multivariate analyses.

RESULTS - A total of 63 low-grade and 38 high-grade small ccRCCs were assessed. Low-grade tumors differed from high-grade tumors with respect to enhancement pattern 1 or 2 (p < 0.001 and p < 0.001), smaller size (p = 0.002 and p = 0.001), and lower attenuation on unenhanced scan (p < 0.001 and p = 0.008). In multivariate analysis, enhancement pattern 1 or 2 and low attenuation (≤30 HU) were identified as independent predictors of low-grade ccRCC. Accuracy derived from logistic regression analysis was 79.2% for reader 1 and 70.3% for reader 2.

CONCLUSIONS - CT imaging features including tumor attenuation and enhancement pattern can be useful to predict the biologic behavior of small ccRCC for adequate treatment strategy.

Abdominal radiology (New York). 2016 Apr 04 [Epub ahead of print]

Soo Yeon Choi, Deuk Jae Sung, Kyung Sook Yang, Kyeong Ah Kim, Suk Keu Yeom, Ki Choon Sim, Na Yeon Han, Beom Jin Park, Min Ju Kim, Sung Bum Cho, Jeong Hyeon Lee

Department of Radiology, Anam Hospital, Korea University College of Medicine, Seoul, South Korea., Department of Radiology, Anam Hospital, Korea University College of Medicine, Seoul, South Korea. Department of Biostatistics, Korea University College of Medicine, Seoul, South Korea., Department of Radiology, Guro Hospital, Korea University College of Medicine, Seoul, South Korea., Department of Radiology, Ansan Hospital, Korea University College of Medicine, Seoul, South Korea., Department of Radiology, Anam Hospital, Korea University College of Medicine, Seoul, South Korea., Department of Radiology, Anam Hospital, Korea University College of Medicine, Seoul, South Korea., Department of Radiology, Anam Hospital, Korea University College of Medicine, Seoul, South Korea., Department of Radiology, Anam Hospital, Korea University College of Medicine, Seoul, South Korea., Department of Radiology, Anam Hospital, Korea University College of Medicine, Seoul, South Korea., Department of Pathology, Anam Hospital, Korea University College of Medicine, Seoul, South Korea.