(Disclaimer: This article is for scientific use only, and relevant information in the following content has been processed to protect patient privacy) Abstract: The subject of this case is Mr. Zhang, who presented with bilateral testicular swelling and azoospermia, at which time a specific manifestation of congenital adrenocortical hyperplasia, a residual adrenal tumor of the testis, was noted. Supplemental treatment with glucocorticoids was given by giving dexamethasone acetate tablets orally. After treatment, Mr. Zhang’s condition has been controlled, all indicators are improving, the testicular swelling is gradually shrinking, and the sperm count in semen is improving. The treatment plan] Drug treatment (dexamethasone acetate tablets) [Treatment cycle] Outpatient treatment for 6 months, with regular follow-up [Treatment effect] The condition has been controlled, and all indicators are improving. Mr. Zhang came to our hospital with the main complaint of “infertility for 3 years and bilateral testicular swelling for 2 years”. The patient reported that he had not had any children since he got married 3 years ago, and that he found bilateral testicular swelling and severe spermatozoa deficiency on semen test 2 years ago, and that he had progressive sperm reduction since then, which worsened to no sperm about 1 year ago. Mr. Zhang has been to major hospitals in and outside the province for many times, but the cause was never clear, and the hospitals only recommended testicular mass surgery, but Mr. Zhang never underwent surgery because he was worried about fertility. Physical examination: height: 164cm, weight: 65kg, slightly darkened skin tone, darkened palm lines, pigmentation of gums, penis length 7cm, left testicular volume 10ml, right testicular volume 10ml, Tanner grading (sexual maturity grading) grade V. Semen routine: no sperm was seen by centrifugal sedimentation. Sex hormones: testosterone 4.15 ng/ml, LH <0.2 mIU/mL, FSH <0.43 mIU/ml, progesterone 11.86 ng/mL, prolactin 13.33 ng/mL. Chromosomal examination: 46xy, AZF normal. Testicular ultrasound suggested: bilateral testicular masses. Pituitary MRI suggested: pituitary microadenoma. This led to the diagnosis of azoospermia, bilateral testicular masses, and pituitary microadenoma. II. Treatment history In view of the specific manifestations of Mr. Zhang's testicular ultrasound and sex hormone levels, there is one disease in particular that needs attention, namely testicular adrenal remnant tumor. Therefore, we focused on asking Mr. Zhang's family if they had performed any adrenal examinations, especially the imaging of the adrenal CT. Mr. Zhang was not examined. I suggested that Mr. Zhang should first undergo CT-enhanced examination of the adrenal glands, and the results suggested multiple nodules in both adrenal glands and a possible large adenoma. Further serum 17-hydroxyprogesterone (17-OHP) levels were found to be significantly elevated. Complete genetic testing revealed two heterozygous mutations in the CYP21A1 gene, which led to a definitive diagnosis of "21-hydroxylase deficiency congenital adrenocortical hyperplasia with testicular adrenal remnant tumors". Accordingly, the first treatment was a consultation with the endocrinology department, and good results were achieved with the formulation of a specific oral dexamethasone acetate tablet. (CT-enhanced examination of adrenal gland) (High-throughput sequencing whole exon gene test report) III. After another period of treatment and medication adjustment, Mr. Zhang's testicular swelling was significantly reduced and his sperm count was significantly improved. Through 6 months of treatment and regular follow-up, the condition was under control, all indicators were improving, the testicular swelling was gradually shrinking, and the sperm count in semen was improving, and Mr. Zhang was very satisfied with the treatment results. IV. Precautions Mr. Zhang did not need to have his testicles removed, but only needed to take medicine to recover, and was very happy for him. Although glucocorticoid and salt corticosteroid replacement therapy is very important for the control of Mr. Zhang's condition, both insufficient and excessive hormone supplementation can cause undesirable results. Therefore, after healing, it is still necessary to regularly monitor hormone levels, testicular swelling and adrenal swelling changes, and to promptly seek medical consultation if uncomfortable symptoms or abnormalities occur. In terms of diet, pay attention to a light diet, eat more spinach and asparagus vegetables, and avoid greasy, spicy and cold foods. Maintain regular work and rest, do not stay up late; moderate exercise, promote physical health, and be well prepared for childbirth. The adrenal remnant tumor of the testis is not a tumor in the true sense of the word, but a tumor-like growth that occurs in the testis and is named adrenal remnant tumor because of the morphological and functional similarity of the proliferating tissue to the adrenal gland. It is a not uncommon benign testicular lesion that should not be overlooked, as the hyperplastic tissue can compress the varicocele and cause peritubular hyalinosis and fibrosis, which can lead to distant obstructive azoospermia and irreversible impairment of testicular interstitial cell function, resulting in reduced testicular spermatogenic function in men. Because of the diverse age of onset, atypical (based on the degree of loss of enzyme activity during adrenocortical steroid hormone synthesis, there are also salt loss and masculinization types) like the present case of Mr. Zhang, the estimated incidence can reach 1/1000, which is very low, so clinicians need to pay enough attention to avoid misdiagnosis and mistreatment. The sperm quality of such patients can be quickly and satisfactorily treated by glucocorticoid supplementation, and the testicular swelling can shrink or even disappear.