Congenital adrenal hyperplasia combined with a huge adrenal myelolipoma of the unilateral adrenal gland in a 51-year-old female: a case report

Background: To report a rare case of classic simple-virilizing congenital adrenal hyperplasia (SV-CAH) caused by 21-hydroxylase deficiency (21-OHD) complicated with a huge unilateral adrenal myelolipoma, and summarize its clinical features, laboratory findings, imaging manifestations, treatment and relevant literature.

Case Description: The clinical data of a 51-year-old female patient with SV-CAH combined with giant left adrenal myelolipoma were retrospectively analyzed, including medical history, physical examination, endocrine laboratory tests, imaging features, surgical treatment and postoperative follow-up results. The patient presented with short stature since childhood, clitoromegaly and primary amenorrhea without salt-wasting manifestations. Peripheral blood karyotype was 46,XX. Endocrine assays showed markedly elevated adrenocorticotropic hormone (ACTH), pregnenolone, 17α-hydroxypregnenolone, 17α-hydroxyprogesterone, and adrenal androgens. Contrast-enhanced computerized tomography (CT) and ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) revealed a large fat-predominant mixed-density mass in the left adrenal gland, compressing the left kidney and surrounding organs. The patient received hydrocortisone replacement therapy and underwent open resection of the left adrenal mass. Pathological examination confirmed adrenal myelolipoma. Post-operative hormone replacement was continued, and partial improvement of steroid hormone levels was observed. Three-month telephone follow-up showed relief of abdominal distension.

Conclusions: Long-term excessive ACTH stimulation in untreated CAH patients promotes the formation of adrenal myelolipoma. Large-size myelolipoma may produce compression symptoms and bleeding risk, which requires surgical intervention. Early diagnosis of CAH and standardized glucocorticoid replacement can mitigate persistent ACTH over-stimulation and reduce the risk of severe adrenal hyperplasia and subsequent large adrenal tumors.