A Single Center Experience of Special Cases: Isolated Adrenal Myelolipoma and Adrenocortical Adenoma with Myelolipomatous Component.

Objective: Isolated adrenal myelolipoma (IAM) is an uncommon, nonfunctioning tumour of the adrenal gland, primarily composed of adipose tissue and hematopoietic trilinear cells. The etiopathogenesis and clinical relevance of this neoplasm remain poorly understood. However, similar myelolipomatous alterations can also occur within adrenocortical adenomas. This report presents our findings on IAM and adrenocortical adenomas with a myelolipomatous component (AMC), focusing on comparing these cases' clinical, demographic, and pathological characteristics.

Methods: Data from twenty patients were retrospectively analyzed, including twelve diagnosed with IAM and eight with AMC, all of whom underwent adrenalectomy. In the IAM cohort, surgical intervention was primarily indicated based on tumour size and/or related symptoms, while in AMC cases, the indication was often driven by hormonal activity.

Results: Patients with IAM had an average age of 52.5 years, with a predominance of female patients (75%). A significant proportion of this group was obese, with concomitant hypertension (HT) and/or type 2 diabetes mellitus (DM). The tumours were predominantly right-sided, with a median size of 69.0 ± 40.0 mm. Notably, 58% of patients with IAM presented with flank or abdominal pain attributed to the mass effect. None of the IAM cases exhibited hormonal activity. Conversely, the AMC group had a younger average age of 46 years, with a high prevalence also in female patients (63%). The tumours were generally smaller, with a median size of 40.0 ± 16.0 mm, and were mostly left-sided. All patients in this group had a history of HT and/or DM, with six exhibiting hormonally active tumours, which manifested as various clinical syndromes, including Cushing syndrome, pheochromocytoma, and Conn syndrome.

Conclusions: While IAM and AMC share several common features, they also demonstrate distinct differences. The presence of endocrinological syndromes was more frequent in AMC cases, whereas IAM cases rarely showed hormonal activity. The most pronounced difference between the two groups was the tumour size at diagnosis, which contributed to the varying clinical presentations upon hospital admission. Furthermore, the high prevalence of obesity, HT, and DM in both groups suggests that these comorbidities may play a role in the development of myelolipomatous patterns observed in these tumours.