Teaching Case

A 21-year-old male patient with congenital adrenal hyperplasia (CAH) known since the age of 1 year and treated with steroid supplementation was referred for a testicular ultrasound because of poor therapy response (elevated serum androgen levels). Physical examination and serum tumour markers were normal.

The testicular ultrasound showed bilateral lobulated predominantly hypoechoic and heterogeneous solid masses with areas of acoustic shadowing in both testes, located near the mediastinum testes (Fig.1). The masses involved approximately half of the testicular parenchyma. On colour Doppler US, the lesions were hypovascular compared to the adjacent testicular parenchyma (Fig. 2). The epididymis was morphologically normal on both sides. There was no hydrocele or varicocele. The imaging findings suggested the diagnosis of bilateral testicular adrenal rest tumour (TART).

CAH is a group of inheritable metabolic diseases affecting the steroid synthesis of the adrenal gland. In most cases, it is caused by 21-hydroxylase deficiency (CYP-21), resulting in insufficient production of cortisol by the adrenal cortex. In this way, the lack of the negative feedback mechanism leads to persistently elevated serum levels of the adrenocorticotrophic hormone (ACTH) [1].

Testicular adrenal rest tumours (TARTs) are benign lesions that develop due to chronically elevated ACTH levels that overstimulates the ectopic adrenal remnant tissue within the testis [2]. In male patients with CAH, TARTs are relatively common, especially in young adults [3].

These tumours are usually asymptomatic and are always benign but may compress the seminiferous tubules and lead to obstructive azoospermia, peritubular fibrosis, and irreversible damage to the surrounding testicular tissue, resulting in infertility [4].

Most of TARTs are difficult to identify on physical examination because of their central location in the testis. Ultrasound is the first line imaging modality in the detection and surveillance of TART [1].

Typical sonographic appearance consists of multiple and bilateral nodular lesions, usually near the testicular mediastinum. Tumour size varies from millimeters to a few centimeters (commonly 3-40 mm). TARTs are most frequently hypoechogenic, but lesions larger than 2 cm can become heterogeneous, hyperechogenic and may harbour calcifications. At colour-Doppler sonography, they typically have a slightly increased vascularity compared to the normal testicular parenchyma, but can also be hypovascular, as in this case [5]. Although the sonographic appearance is variable, in the appropriate clinical context of hormonal abnormalities associated with CAH no further imaging workup is necessary.

Intensive corticosteroid therapy is the first line treatment option. If enlargement of the lesion persists, testis-sparing surgery may be applied. Screening for TARTs using ultrasound is important in male patients with CAH for early-detection and prevention of potential complications, such as infertility [2].

Awareness of these benign tumours in the context of CAH is crucial for confident diagnosis, and to enable appropriate treatment that prevents infertility and to avoid unnecessary testicular biopsies and orchiectomies.

Written informed patient consent for publication has been obtained.