Mature teratoma of the adrenal gland presenting as an adrenal incidentaloma

A female in her 20s presented with right upper abdominal pain, and imaging revealed a fat- and calcification-containing adrenal mass, raising suspicion for an adrenal teratoma. Hormonal evaluation, including plasma metanephrine and overnight dexamethasone suppression test, ruled out functional adrenal pathology. Intraoperatively, a lobulated mass arising from the right adrenal gland was found to be adherent to the inferior vena cava and surrounding structures. En bloc resection was performed with preservation of adjacent organs. Histopathology confirmed a mature adrenal teratoma with components derived from all three germ layers, including bone, adipose tissue, neural elements and mucin-secreting epithelium. Postoperative recovery was uneventful. This case highlights the importance of considering teratoma in the differential diagnosis of adrenal incidentalomas with mixed-density features on imaging. Accurate preoperative assessment and complete surgical excision are critical for diagnosis and favourable outcomes.