As the “hyperplasia” term stands, a common imaging finding in CAH is a diffuse enlargement of both adrenal glands, while preserving their typical shape and heterogeneous post-contrast enhancement on CT and MRI (Figs. 12.1, 12.2, and 12.3) [1, 6–14]. Interestingly, adrenal size is positively correlated with plasma concentration of dehydroepiandrosterone sulphate [15]. However, it is very important to note that an imaging finding of normal adrenal glands does not exclude the possibility of CAH [16–18]. Also, imaging appearance in CAH may have no difference from ACTH-dependent Cushing’s syndrome (Figs. 12.4 and 12.5), in which fertility is often impaired due to hypercortisolism (Table 12.1).

Girls with any kind of 21OH-CAH may develop reproductive problems such as oligomenorrhea or amenorrhea in adolescence [4, 5]. Other problems that can occur are vaginal insufficiency with dyspareunia, and secondary polycystic ovary syndrome from adrenal-derived androgens [3]. The increased incidence of polycystic ovaries is a common finding in mild CAH, but also in the classic form, and it may contribute to infertility [5]. About 40% of patients with non-classic CAH have polycystic ovaries (Fig. 12.6). Pregnancy rates of 50% have been reported in untreated patients with non-classic CAH compared with 93–100% after treatment, but these data are mainly from studies with symptomatic women; thus, the overall rate for all 21OH-CAH women may be lower [5].

Most men with CAH have no fertility-related problems, presenting with normal sperm counts and being able to father children. Nonetheless, a high incidence of testicular adrenal rest tumors (TART) have been reported in men with CAH, with a prevalence of up to 94% determined by ultrasound (US) [19]. In males with salt-wasting CAH, TART may be accompanied by deficient spermatogenesis [20, 21], and medical treatment consists of pituitary suppression with dexamethasone, since tumors are usually responsive to corticotropin. Ultrasound findings include bilateral intratesticular hypoechoic lobulated masses surrounding the mediastinal testis (Fig. 12.7) [22]. TART are mainly hypo or avascular on color Doppler ultrasound (CDUS) [23] and cause no course deviation or changes in caliber of locoregional vessels [22, 23]. In some cases, TART may appear as heterogeneous or hyperechoic nodules [22–26], which may represent fibrosis or calcifications [23]. MRI may help differentiate testicular mass lesions in selected cases where ultrasound findings are not definitive, and TART appears as a relatively hypointense lobulated mass on T2-weighted sequences located adjacent to testicular mediastinum, as in ultrasound (Fig. 12.8) [27]. On follow-up, TART can vary in size [25], but the size seems to have no correlation with hormonal control or hormonal markers [21, 25, 28]. As TART may be responsible for reduced fertility, occurring even in young children with a prevalence of 21–24% [29, 30], and with data suggesting that gonadal dysfunction is already present before puberty, the early detection of testicular lesions is advised to improve treatment and prevent longstanding gonadal impairment function [29, 31]. Moreover, it is important to note that the first major mechanism of impaired fertility in men with 21OH-CAH is gonadotropin suppression from adrenal-derived androgens, which causes testicular atrophy and impairs spermatogenesis [3].