Genetic and clinical characteristics including occurrence of testicular adrenal rest tumors in Slovak and Slovenian patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency.

Objective: To analyze the mutational spectrum, clinical characteristics, genotype-phenotype correlations, testicular adrenal rests tumor prevalence, and role of neonatal screening in congenital adrenal hyperplasia (CAH) patients from Slovakia and Slovenia. Design and methods: Data were obtained from 104 patients with CAH registered in Slovak and Slovenian databases. Low-resolution genotyping was performed to detect the most common point mutations. To detect deletions, conversions, point mutations, or other sequence changes in the CYP21A2 gene, high-resolution genotyping was performed. Genotypes were classified according to residual 21-hydroxylase activity (null, A, B, C). Results: 64% of the individuals had the salt-wasting form (SW-CAH), 15% the simple virilizing form (SV-CAH), and 21% the non-classic (NC-CAH). CYP21A2 gene deletion/conversion and c.293-13A/C>G pathogenic variant accounted together for 55.5% of the affected alleles. In SV-CAH p.Ile172Asn was the most common pathogenic variant (28.13%), while in NC-CAH p.Val282Leu (33.33%), CYP21A2 gene deletion/conversion (21.43%), c.293-13A/C>G (14.29%), Pro30Leu (11.90%). The frequency of alleles with multiple pathogenic variants was higher in Slovenian patients (15.83% of all alleles). Severe genotypes (0 and A) correlated well with the expected phenotype (SW in 94.74% and 97.3%), while less severe genotypes (B and C) correlated weaklier (SV in 50% and NC in 70.8%). The median age of SW-CAH patients at the time of diagnosis was 6 days in Slovakia vs. 28.5 days in Slovenia (p=0.01). Most of the Slovak patients in the cohort were detected by NBS. (24 out of 29). TARTs were identified in 7 out of 24 male patients, of whom all (100%) had SW-CAH and all had poor hormonal control. The median age at the diagnosis of TARTs was 13 years. Conclusion: The study confirmed the importance of neonatal screening, especially in the speed of diagnosis of severe forms of CAH. The prediction of the 21-OH deficiency phenotype was reasonably good in the case of severe pathogenic variants, but less reliable in the case of milder pathogenic variants, which is consistent compared to data from other populations. Screening for TARTs should be realized in all male patients with CAH, since there is possible remission when identified early.

Genotype of congenital adrenal hyperplasia patients with testicular adrenal rest tumor.

Testicular adrenal rest tumor (TART) is one of the important complications that can cause infertility in male patients with congenital adrenal hyperplasia (CAH) and should therefore be diagnosed and treated at an early age. The factors that result in TART in CAH have not been completely understood. The aim of this study is to evaluate the genotype-phenotype correlation in CAH patients with TART. METHOD: Among 230 malepatients with CAH who were followed upwith regular scrotal ultrasonography in 11 different centers in Turkey, 40 patients who developed TARTand whose CAH diagnosis was confirmed by genetic testing were included in this study. Different approaches and methods were used for genotype analysis in this multicenter study. A few centers first screened the patients for the ten most common mutations in CYP21A2 and performed Sanger sequencing for the remaining regions only if these prior results were inconclusive while the majority of the departments adopted Sanger sequencing for the whole coding regions and exon-intron boundaries as the primary molecular diagnostic approach for patients with either CYP21A2 orCYP11B1 deficiency. The age of CAH diagnosis and TART diagnosis, type of CAH, and identified mutations were recorded. RESULTS: TART was detected in 17.4% of the cohort [24 patients with salt-wasting (SW) type, four simple virilizing type, and one with nonclassical type with 21-hydroxylase (CYP21A2) deficiency and 11 patients with 11-beta hydroxylase (CYP11B1) deficiency]. The youngest patients with TART presenting with CYP11B1 and CYP21A2 deficiency were of 2 and 4 years, respectively. Eight different pathogenic variants in CYP21A2were identified. The most common genotypes were c.293-13C>G/c.293-13C>G (31%) followed by c.955C>T/c.955C>T(27.6%) and c.1069C>T/c.1069C>T (17.2%). Seven different pathogenic variants were identified in CYP11B1. The most common mutation in CYP11B1 in our study was c.896T>C (p.Leu299Pro). CONCLUSION: We found that 83% TART patients were affected with SW typeCYP21A2 deficiency,and the frequent mutations detected were c.955C>T (p.Gln319Ter), c.293-13C>G in CYP21A2 and c.896T>C (p.Leu299Pro) inCYP11B1. Patients with CYP11B1 deficiency may develop TART at an earlier age. This study that examined the genotype-phenotype correlation in TART may benefit further investigations in larger series.

Transcriptional comparison of testicular adrenal rest tumors with fetal and adult tissues.

Background: Testicular adrenal rest tumors (TART) are a common complication of unknown cellular origin in patients with congenital adrenal hyperplasia (CAH). These benign tumors have both adrenal and testicular characteristics and are hypothesized to either derive from cells of adrenal origin from the fetal adrenogonadal primordium or by atypical differentiation of adult Leydig-progenitor cells. Objective: This study aims to unravel the identity and etiology of TART. Methods: Co-expression of adrenal-specific CYP11B1 and Leydig cell-specific HSD17B3 in TART was studied using immunohistochemistry. We studied the possibility of TART being derived from atypical differentiation of adult Leydig-progenitor cells by the quantification of adrenal-specific enzyme expression upon adrenocorticotrophic hormone (ACTH)-like stimulation of ex vivo cultured platelet-derived growth factor receptor alpha-positive cells. By comparing the transcriptome of TART (n = 16) with the transcriptome of fetal adrenal (n = 13), fetal testis (n = 5), adult adrenal (n = 11), and adult testis (n = 10) tissues, we explored the identity of TART. Results: We demonstrate co-expression of adrenal-specific CYP11B1 and testis-specific HSD17B3 in TART cells, indicating the existence of a distinct TART cell exhibiting both adrenal and testicular characteristics. Ex vivo cultured adult Leydig-progenitor cells did not express the ACTH-receptor MC2R but did express CYP11B1 upon stimulation. Unsupervised clustering of transcriptome data showed that TART was most similar to adult adrenal tissue, followed by adult testis tissue, and least similar to either fetal tissue. Conclusion: Our data suggest that TART is induced - most likely via activation of a cAMP/protein kinase A-dependent receptor - from a progenitor cell into a unique mature adrenal-like cell type, sometimes exhibiting both adrenal and testicular features.

Production of 11-Oxygenated Androgens by Testicular Adrenal Rest Tumors.

CONTEXT: Testicular adrenal rest tumors (TART) are a common complication in males with classic 21-hydroxylase deficiency (21OHD). TART are likely to contribute to the androgen excess in 21OHD patients, but a direct quantification of steroidogenesis from these tumors has not been yet done. OBJECTIVE: We aimed to define the production of 11-oxygenated 19-carbon (11oxC19) steroids by TART. METHODS: Using liquid chromatography-tandem mass spectrometry, steroids were measured in left (n = 7) and right (n = 4) spermatic vein and simultaneously drawn peripheral blood (n = 7) samples from 7 men with 21OHD and TART. For comparison, we also measured the peripheral steroid concentrations in 5 adrenalectomized patients and 12 age- and BMI-matched controls. Additionally, steroids were quantified in TART cell- and adrenal cell-conditioned medium, with and without adrenocorticotropic hormone (ACTH) stimulation. RESULTS: Compared with peripheral blood from 21OHD patients with TART, the spermatic vein samples displayed the highest gradient for 11ß-hydroxytestosterone (11OHT; 96-fold) of the 11oxC19 steroids, followed by 11-ketotestosterone (47-fold) and 11ß-hydroxyandrostenedione (11OHA4; 29-fold), suggesting production of these steroids in TART. TART cells produced higher levels of testosterone and lower levels of A4 and 11OHA4 after ACTH stimulation compared with adrenal cells, indicating ACTH-induced production of testosterone in TART. CONCLUSION: In patients with 21OHD, TART produce 11oxC19 steroids, but in different proportions than the adrenals. The very high ratio of 11OHT in spermatic vs peripheral vein blood suggests the 11-hydroxylation of testosterone by TART, and the in vitro results indicate that this metabolism is ACTH-sensitive.

Case Report:clinical experience of bilateral giant pediatric Testicular adrenal rest tumors with 3 Beta-Hydroxysteroid Dehydrogenase-2 family history.

BACKGROUND: We reported a patient with Testicular adrenal rest tumors(TARTs) caused by congenital adrenal hyperplasia(CAH). TARTs occur frequently in CAH population with 21-hydroxylase deficiency(21-OHD). There are few reports of TARTs with 3ß-hydroxysteroid dehydrogenase deficiency-2 (3ß-2HSD).Furthermore,gaint TARTs are rarely mentioned in reported cases involving affected siblings. CASE PRESENTATION: A 14-year-old male patient was admitted by congenital adrenal hyperplasia with progressively increasing bilateral testicular masses.The Patient and his elder brother had been performed mutational and chromosome analysis and biopsy. Hormonal and anthropometric measurements were performed during endocrine treatments. We successfully performed surgery and excised two 83mm×46mm×44mm and 74mm×49mm×31mm tumors. Our pathology and immunochemistry tests have proven TARTs in patient. At first, both siblings received regular doses of hydrocortisone and fludrocortisones and tumor size regressed. During the one-year irregular intake due to Covid-19 pandemic, endocrine treatment became insensitive and tumor size slowly increased. The gene analysis reported two novel mutations C.776 C>T and C.674 T>A. The C.776 C>T is from father and has been reported. The C.674 T>A inherited from mother and cannot found in gene library and may related to TARTs. CONCLUSIONS: This case illustrates inadequate hormone therapy could cause tumor enlargement. It is essential to seek for ultrasound examination once suspected scrotal mass occurred.It is necessary to adjust endocrine medicine or adopt surgery in refractory gaint TARTs. And presence of tunica vaginalis cavity may indicate the severity of TARTs in surgery.

Long-term outcome of partial P450 side-chain cleavage enzyme deficiency in three brothers: the importance of early diagnosis.

OBJECTIVE: CYP11A1 mutations cause P450 side-chain cleavage (scc) deficiency, a rare form of congenital adrenal hyperplasia with a wide clinical spectrum. We detail the phenotype and evolution in a male sibship identified by HaloPlex targeted capture array. FAMILY STUDY: The youngest of three brothers from a non-consanguineous Scottish family presented with hyperpigmentation at 3.7 years. Investigation showed grossly impaired glucocorticoid function with ACTH elevation, moderately impaired mineralocorticoid function, and normal external genitalia. The older brothers were found to be pigmented also, with glucocorticoid impairment but normal electrolytes. Linkage studies in 2002 showed that all three brothers had inherited the same critical regions of the maternal X chromosome suggesting an X-linked disorder, but analysis of NR0B1 (DAX-1, adrenal hypoplasia) and ABCD1 (adrenoleukodystrophy) were negative. In 2016, next-generation sequencing revealed compound heterozygosity for the rs6161 variant in CYP11A1 (c.940G>A, p.Glu314Lys), together with a severely disruptive frameshift mutation (c.790_802del, K264Lfs*5). The brothers were stable on hydrocortisone and fludrocortisone replacement, testicular volumes (15-20 mL), and serum testosterone levels (24.7, 33.3, and 27.2 nmol/L) were normal, but FSH (41.2 µ/L) was elevated in the proband. The latter had undergone left orchidectomy for suspected malignancy at the age of 25 years and was attending a fertility clinic for oligospermia. Initial histology was reported as showing nodular Leydig cell hyperplasia. However, histological review using CD56 staining confirmed testicular adrenal rest cell tumour (TART). CONCLUSION: This kinship with partial P450scc deficiency demonstrates the importance of precise diagnosis in primary adrenal insufficiency to ensure appropriate counselling and management, particularly of TART.

Testicular Adrenal Rest Tumors: Current Insights on Prevalence, Characteristics, Origin, and Treatment.

This review provides the reader with current insights on testicular adrenal rest tumors (TARTs), a complication in male patients with congenital adrenal hyperplasia (CAH). In recent studies, an overall TART prevalence of 40% (range, 14% to 89%) in classic patients with CAH is found. Reported differences are mainly caused by the method of detection and the selected patient population. Biochemically, histologically, and molecularly, TARTs exhibit particular adrenal characteristics and were therefore thought to originate from aberrant adrenal cells. More recently, TARTs have been found to also exhibit testicular characteristics. This has led to the hypothesis of pluripotent cells as the origin of TARTs. High concentrations of ACTH could cause hyperplasia of these pluripotent cells, as TARTs appear to be associated with poor hormonal control with concomitant elevated ACTH. Unfortunately, as yet there are no methods to prevent the development of TARTs, nor are there guidelines to treat patients with TARTs. Intensified glucocorticoid treatment could improve fertility status in some cases, although studies report contradicting results. TARTs can also lead to irreversible testicular damage, and therefore semen cryopreservation could be offered to patients with TARTs. Further research should focus on the etiology and pharmacological treatment to prevent TART development or to treat TARTs and improve the fertility status of patients with TARTs.

Testicular Adrenal Rest Tumor in Two Brothers with a Novel Mutation in the 3-Beta-Hydroxysteroid Dehydrogenase-2 Gene.

Testicular adrenal rest tumors (TART) occur frequently in adolescents and adults with 21-hydroxylase deficiency. There have been no reports of TART in children with 3ß-hydroxysteroid dehydrogenase deficiency (HSD3ß). Biopsy proven TART was diagnosed in a 31/12-year-old male patient and also in his 22-month-old sibling. Hormonal and anthropometric measurements were performed during glucocorticoid and fludrocortisone treatment. The mutational analysis was performed by direct DNA sequencing of the complete coding region of the HSD3ß2 gene. Initially, both siblings were treated with high doses of hydrocortisone and fludrocortisone. TART regressed with dexamethasone treatment in both patients. However, growth velocity decreased and weight gain increased in both patients. Dexamethasone was changed to high-dose hydrocortisone (>20 mg/m2/d). Sequencing analyses revealed a novel homozygous p.W355R (c.763 T>C) mutation at exon 4 of the HSD3ß2 gene in both siblings. These two patients are, to our knowledge, the first known cases of TARTs with a novel mutation in the HSD3ß2 gene detected during childhood. High-dose hydrocortisone treatment is more reliable for TART in children.

Abundance of DLK1, differential expression of CYP11B1, CYP21A2 and MC2R, and lack of INSL3 distinguish testicular adrenal rest tumours from Leydig cell tumours.

OBJECTIVE: Testicular adrenal rest tumours (TARTs) are a common finding in patients with congenital adrenal hyperplasia (CAH). These tumours constitute a diagnostic and management conundrum and may lead to infertility. TART cells share many functional and morphological similarities with Leydig cells (LCs), and masses consisting of such cells are occasionally misclassified as malignant testicular tumours, which may lead to erroneous orchiectomy in these patients. DESIGN: In this study, we aimed to investigate the potential of LC developmental markers and adrenal steroidogenic markers in the differential diagnosis of TARTs and malignant LC tumours (LCTs). METHODS: We investigated mRNA and protein expression of testicular steroidogenic enzymes; CYP11A1 and HSD3B1/2, markers of adrenal steroidogenesis; CYP11B1, CYP21A2 and ACTH receptor/melanocortin 2 receptor (MC2R), and markers of LC maturation; and delta-like 1 homolog (DLK1) and insulin-like 3 (INSL3) in testicular biopsies with TART, orchiectomy specimens with LCTs and samples from human fetal adrenals. RESULTS: Expression of testicular steroidogenic enzymes was observed in all specimens. All investigated adrenal steroidogenic markers were expressed in TART, and weak reactions for CYP11B1 and MC2R were observed at the protein level in LTCs. TART and fetal adrenals had identical expression profiles. DLK1 was highly expressed and INSL3 not detectable in TART, whereas INSL3 was highly expressed in LCTs. CONCLUSIONS: The similar expression profiles in TART and fetal adrenals as well as the presence of classical markers of adrenal steroidogenesis lend support to the hypothesis that TART develops from a displaced adrenal cell type. Malignant LCTs seem to have lost DLK1 expression and do not resemble immature LCs. The different expression pattern of DLK1, INSL3 and most adrenocortical markers adds to the elucidation of the histogenesis of testicular interstitial tumours and may facilitate histopathological diagnosis.

Molecular characterization of testicular adrenal rest tumors in congenital adrenal hyperplasia: lesions with both adrenocortical and Leydig cell features.

CONTEXT: Testicular adrenal rest tumors (TART) are one of the major long term complications in patients with congenital adrenal hyperplasia. Although several adrenal-like properties have been assigned to these benign lesions, the etiology has not been confirmed yet. OBJECTIVE: The aim of this study was to describe TART in more detail by analyzing several (steroidogenic) characteristics that may be classified as adrenal cortex or Leydig cell specific. METHODS: Gene expression analysis by qPCR was performed for 14 genes in TART tissue (n = 12) and compared with the expression in healthy control fibroblasts (nonsteroidogenic control). In addition, a comparison was made with the expression levels in testis tissue (n = 9) and adrenal tissue (n = 13). RESULTS: Nearly all genes were highly expressed in TART tissue, including all genes that encode the key steroidogenic enzymes. TART expression levels are in the majority almost identical to those found in adrenal tissue. The expression of adrenal cortex specific genes (CYP11B1, CYP11B2, and MC2R) in both TART and adrenal tissue is approximately 1000-10 000 times higher compared to that in testes samples. In addition, the Leydig cell markers INSL3 and HSD17B3 were not only found in testes, but also in TART, both at significantly higher levels than in the adrenal (p < 0.01). CONCLUSION: Our study shows for the first time that TART have multiple steroidogenic properties, which include not only the expression of adrenal cortex but also of Leydig cell markers. Therefore, the origin of these tumors might be a more totipotent embryonic cell type.

Increased prevalence of testicular adrenal rest tumours during adolescence in congenital adrenal hyperplasia.

UNLABELLED: Testicular adrenal rest tumours (TART) are one of the most important causes of infertility in adult male patients with congenital adrenal hyperplasia (CAH). These benign tumours are already detected in children, but screening of TART is not routinely performed. OBJECTIVE: To define retrospectively the prevalence of TART in 41 paediatric male CAH patients aged 0-19 years regularly followed by high-frequency (Fcentral 12-MHz) ultrasound techniques. RESULTS: Above the age of 10 years, there was a clear increase in the prevalence of TART: 10-12 years, 28% (2 of 7 patients), 13-14 years, 50% (4/8), and 15-16 years, 75% (3/4). Above the age of 16 years, TART were detected in 100% of the patients (7/7). The tumours were not detectable by palpation. CONCLUSION: TART is already present in childhood with an increasing prevalence after onset of puberty. We recommend regular ultrasound from the onset of puberty in all boys with classic CAH.

Management of CAH during pregnancy: optimizing outcomes.

PURPOSE OF REVIEW: Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is one of the most common autosomal recessive disorders. In the past, pregnancy was considered to be unlikely for women with CAH, particularly the classical forms. The purpose of this review is to provide current information regarding the pathophysiology of CAH, factors relevant for female and male fertility, and recommendations for management during pregnancy. RECENT FINDINGS: Individuals with CAH, both female and male, have reduced fertility. For women, chronic anovulation, elevated progestin levels, and aberrant endometrial implantation have been identified as reasons for the subfertility. Testicular adrenal rest tumors, oligospermia, and hypogonadotropic hypogonadism are frequently associated with subfertility in men with all forms of CAH. SUMMARY: Adequate suppression of progesterone appears to be an essential aspect of preconception management for women. Most importantly, treatment needs to be individualized. Awareness of these factors and appropriate therapeutic interventions can lead to successful outcome defined as a healthy live born infant.

Total adrenal volume but not testicular adrenal rest tumor volume is associated with hormonal control in patients with 21-hydroxylase deficiency.

CONTEXT: Patients with 21-hydroxylase deficiency (21-OHD) have been shown to develop adrenal adenomas and, in males, testicular adrenal rest tumors (TARTs) at a high percentage. OBJECTIVE: The aim of this study was to evaluate the interrelation of adrenal masses and TARTs as well as factors stimulating tumor growth of orthotopic and ectopic adrenal tissue in 21-OHD. DESIGN: In a cross-sectional study, 26 adult male patients with classic 21-OHD (15 salt wasting, 11 simple virilizing; age range, 18-48 yr) were clinically assessed according to their hormonal control. Magnetic resonance imaging of the adrenals (26 of 26) and of the testes (18 of 26) was performed. Adrenal size and morphology was compared to 26 age-matched controls. RESULTS: Combined adrenal volume of 21-OHD patients was significantly higher (median, 9.3 ml; range, 3.2-124.5 ml) in comparison to controls (median, 7.4 ml; range, 5.5-10.8 ml; P = 0.005). Morphologically, adrenals were classified as normal without nodules in 27% of 21-OHD patients compared to 69% of controls. None of the controls, but 42% of 21-OHD patients had an overall adrenal volume higher than 11 ml. Ten of 18 patients had TARTs with a median volume of 3.3 ml (range, 0.4-21.6 ml). Total adrenal volume and tumor size but not TART volume correlated positively with current parameters of hormonal control (androstenedione, morning 17-OHP in serum, pregnanetriol in 24-h urine; P < 0.001 for each). Baseline ACTH was independent of adrenal and TART volume. There was no correlation of total adrenal or adrenal tumor size with TART volume. CONCLUSION: These data provide indirect evidence that different factors regulate the growth of orthotopic adrenal tissue and ectopic adrenal remnants in TARTs.

Testicular adrenal rest tumours in boys, adolescents and adult men with congenital adrenal hyperplasia may be associated with the CYP21A2 mutation.

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder with impaired function of the adrenal cortex caused by mutations in the CYP21A2 gene. Deficiency of steroid 21-hydroxylase accounts for 80-95% of CAH cases. Testicular adrenal rest tumours (TART) may be prevalent in up to 95% of CAH adults and may already appear during childhood. Whether genotype sub-types can account for the development of TART has not been investigated previously. We therefore investigated this by coupling clinical information of CAH patients with information of their genetic mutation. In 49 male patients (age 2.6-40.3 years) with 21-hydroxylase deficiency, testicular ultrasound examinations were performed and CYP21A2 genotypes determined. These were grouped according to the residual 21-hydroxylase activity: group Null (complete enzyme impairment), group A (almost complete enzyme impairment), group B (severe enzyme impairment) and group C (partial impairment). TART were observed in 27 of 49 patients (55%). For the 23 patients younger than 18 years, TART were present in 11 (48%), the youngest patient being 7.5 years old. The presence of TART was dependent on the CYP21A2 genotype: 27 of 37 patients (73%) with the most severe mutations (groups Null and A) had TART, whereas none of 12 patients with the milder mutations (groups B and C) had TART. We conclude that TART were most frequently detected in patients with severe CYP21A2 mutations, and may occur already in early childhood in such patients.

Testicular adrenal rest tumors and Leydig and Sertoli cell function in boys with classical congenital adrenal hyperplasia.

CONTEXT: Infertility observed in adult males with congenital adrenal hyperplasia (CAH) has been associated with testicular adrenal rest tumors (TART) that may originate during childhood. OBJECTIVE: Our objective was to describe the prevalence of TART and Sertoli and Leydig cell function in a group of boys aged 2-10 yr with CAH and to compare prevalence with that of a control group. DESIGN: From August 2005 to January 2007, 19 patients with classical CAH (CAH group) were referred from seven endocrinology centers. METHODS: We studied 19 subjects in the CAH group and, as a control group, 13 boys from the community that did not have testicular diseases. A complete physical exam was performed. High-resolution ultrasound was used to determine TART prevalence. Inhibin B and anti-Müllerian hormone were used as Sertoli cell markers. The ratio between basal testosterone levels and testosterone levels 72 h after beta-human chorionic gonadotropin (5000 U/m2) treatment [(T72- T0)/T0] was used to evaluate Leydig cell response. RESULTS: CAH and control groups were comparable in chronological age (5.9 vs. 5.6 yr; P = 0.67) and bone age/chronological age ratio (1.09 vs. 1.03; P = 0.09). TART prevalence was four of 19 (21%) in the CAH group. Lower values for inhibin B (49.2. vs. 65.2 pg/ml; P = 0.018), anti-Müllerian hormone (70.1 vs. 94.2 ng/ml; P = 0.002), and (T72- T0)/T0 (5.6 vs. 13.6; P < 0.01) were observed in the CAH group. CONCLUSION: TART in prepubertal males with classic CAH could be found during childhood. We also report differences in markers of gonadal function in a subgroup of patients, especially in those with inadequate control.

Testicular tumors in patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency show functional features of adrenocortical tissue.

CONTEXT: In male patients with congenital adrenal hyperplasia (CAH), testicular adrenal rest tumors are frequently found that may interfere with gonadal function. OBJECTIVE: Our objective was to determine steroid-producing features of testicular adrenal rest tumors. DESIGN AND SETTING: The study is descriptive and took place at a university medical center. PATIENTS: Eight adult CAH patients with bilateral testicular adrenal rest tumors were treated with testis-sparing surgery. INTERVENTIONS: In all but one patient, spermatic veins were cannulated during surgery and blood samples collected to measure the adrenal-specific steroid 21-deoxycortisol (21DF) and 17-hydroxyprogesterone (17OHP) and androstenedione (A). The same parameters were measured in simultaneously taken peripheral blood. mRNA concentrations of adrenal-specific enzymes CYP11B1 and CYP11B2 and ACTH and angiotensin II (AII) receptors were measured in tumor tissue. MAIN OUTCOME MEASURES: Adrenal-specific steroids/enzymes were assessed. RESULTS: 21DF, 17OHP, and A levels were measurable in all spermatic vein samples. The ratio (mean +/- SD) between spermatic vein and simultaneously taken peripheral blood samples was 37.8 +/- 56.3 (21DF), 132.0 +/- 249 (17OHP), and 57.0 +/- 68.2 (A). CYP11B1, CYP11B2, and ACTH and AII receptor mRNAs were detected in all tumors with a strong correlation between ACTH receptor mRNA in tumors and 21DF (r = 0.85; P = 0.015), 17OHP (r = 1; P = 0.01) and A (r = 0.89; P = 0.007) concentrations in peripheral blood. CONCLUSION: Testicular adrenal rest tumors produce adrenal-specific steroids and express adrenal-specific enzymes and ACTH and AII receptors, confirming the strong resemblance with adrenal tissue. Because AII receptors are present in tumor tissue, it can be hypothesized that AII may be an additional factor responsible for testicular adrenal rest tumor growth.