Sonographic evaluation of hypertrophy of septum of Bertin.

Sonography was utilized to evaluate 12 patients with hypertrophy of the septum of Bertin. To confirm the diagnosis, angiography was used in 7 patients and radionuclide imaging in 2. Three sonographic characteristics were found: (1) an isoechogenic, ellipsoid mass with an echogenic linear rim of renal sinus fat; (2) contiguity of the mass with a normal-placed septum of Bertin; and (3) the occurrence of the mass effect always at the level of the emergence of the renal vein. The sonographic findings could be divided into two definite types. Type I showed moderate hypertrophy with a mass effect ranging from 1.1 by 2.3 cm to 2.0 by 3.2 cm in diameter, usually presenting with a smooth contour and discrete mass effect on the intravenous pyelogram (IVP). Type II showed severe hypertrophy with a mass effect ranging from 3.2 by 4.0 cm to 3.5 by 4.5 cm in diameter, usually presenting with a lobulated contour and irregular stretching of the calyceal system on IVP. The differential diagnosis is discussed. In conclusion, we found that sonography associated with excretory urography is an accurate method for the diagnosis of hypertrophy of the septum of Bertin.