Endocrine Abstracts

Introduction: Myelolipomas account for 5–15% of all resected adrenal masses and are considered as benign lesions consisting of fat and myeloid tissue. Their pathogenesis is mostly unknown, though altered mesenchymal stem cell function or a sustained respond to increased ACTH stimulation are discussed. Even though these findings are partly inconclusive, an increased incidence of myelolipoma in patients with congenital adrenal hyperplasia (CAH) has been reported, which may lead to increased ACTH levels if CAH is not treated adequately. Due to massive growth in a displacing manner with possible rupture and intra-abdominal bleeding, as well as difficulties to distinguish them from malignant lesions, surgical resection is often recommended. Thus, incidental findings may have therapeutic consequences and routine adrenal imaging in patients with congenital adrenal hyperplasia should be considered.

Case report: A 48-year-old male with congenital adrenal hyperplasia and salt-wasting syndrome due to 21-hydroxylase-deficiency presented frequently for medical surveillance in our outpatient clinic. With 0.05 mg fludrocortisone, a daily dose of 10 mg hydrocortisone complemented by 5 mg prednisolone in the evening, the patient showed no clinical symptoms and his laboratory results were within the reference range. During a routine visit the patient underwent abdominal screening by ultrasound. This examination revealed huge bilateral hyperechogenic adrenal masses (3.6 × 9.5 cm in the right, 10.4 × 10.4 cm in the left adrenal gland). We performed a contrast-enhanced sonography, that showed an early arterial peak enhancement (after 17 seconds) without any significant wash-out, which is consistent with bilateral adrenal myelolipomas. Additional MRI using opposed-phase sequence supported the suspected diagnosis. However soft tissue sarcoma was still a potential differential diagnosis. Due to size and possible malignancy at the MRI scan, bilateral adrenalectomy was performed and a mass of 1083 g at the left and 96 g at the right adrenal gland was extracted. Histopathological diagnosis was bilateral adrenal myelolipoma as anticipated by the previous findings.

Conclusion: We conclude that due to the increased frequency of adrenal masses and potentially needed therapeutic interventions, patients with CAH should receive imaging of the adrenal glands. Because myelolipomas can be identified by ultrasound (US) with high sensitivity and specificity, US should be considered as the imaging modality of choice. If malignancy is suspected due to ultrasound criteria, contrast-enhanced-ultrasound or CT/MRI should be considered. Further epidemiological studies are needed to define the incidence of adrenal masses in patients with CAH and to examine the pathogenesis of this disease.