Testicular adrenal rest tumours in postpubertal males with congenital adrenal hyperplasia: sonographic and MR features

The purpose of this study was to investigate the prevalence of testicular adrenal rest tumours in patients with congenital adrenal hyperplasia (CAH), and to describe sonographic and MR features of these lesions. Seventeen postpubertal male CAH patients underwent scrotal sonography, with colour Doppler, and in 16 of them pre- and postcontrast enhanced T1- and T2-weighted MR images of the testes were obtained. Ultrasound revealed lesions in 16 of 17 patients (94%), bilateral in 10 patients and unilateral in 6 patients. The lesions were typically located adjacent to the mediastinum testis. The maximal diameter of the lesions varied from 2 to 40 mm. Margins were blurred in 11 of 31 lesions. Seventeen of the 20 lesions smaller than 2 cm in diameter were hypoechoic, whereas all 11 lesions larger than 2 cm showed hyperechoic reflections. On MR all lesions were isointense on T1- and hypointense on T2-weighted images and lesion margins were clearly defined. Enhancement of the lesions after intravenous contrast was seen in 13 of 15 patients. In our series the prevalence of testicular adrenal rest tumours in postpubertal CAH patients is much higher than in other reported studies. The lesions may develop from some small, hypoechoic, and multifocal nodules and coalesce to large hypoechoic lesions with hyperechoic reflections on ultrasound. As our results suggest that ultrasonography and MR show the lesions equally well, ultrasonography should be the method of first choice for detection and follow-up of these lesions, because it is the cheapest and quickest imaging technique. In case of a partial orchiectomy, MR is recommended because it shows lesion margins optimally.