Lim RS, et al. - In the present study, the researchers assessed previously described growth patterns in < 4 cm solid renal masses. For the purpose of this investigation, 63 renal cell carcinomas and 36 benign masses from a single institution were independently assessed by two blinded radiologists (R1/R2) using T2-weighted MRI for the angular interface sign (AIS), bubble-over sign (BOS), percentage (%) exophytic growth and long-to-short axis ratio with IRB approval. Using ANOVA, chi-square and multi-variate regression, comparisons were performed. Findings revealed that greater exophytic growth was linked with benignity among solid renal masses. It was noted that only minimal fat angiomyolipomas (AMLs) and oncocytomas had 90-100% exophytic growth.