7446 Primary Adrenal Mature Teratoma Initially Diagnosed As An Adrenal Myelolipoma

Abstract Disclosure: A. White-Cotsmire: None. B. Kodali: None. A.M. Avram: None. S.S. Shah: None. Background: Teratomas are a type of germ cell tumor containing different types of tissue (e.g., hair, teeth, bone adipose, muscle). Most teratomas are benign (i.e., mature), but they may also be malignant (i.e., immature). Both immature and mature teratomas contain derivatives of ectoderm, endoderm, and mesoderm; however, immature teratomas are differentiated by the presence of embryonic, usually neuroectodermal, tissue. Mature teratomas have the potential for malignant transformation (1–2% of cases), usually squamous cell carcinoma within the teratoma. Extra-gonadal teratomas are rare (only 1–5%); reported locations include sacrococcygeal, head and neck, retroperitoneum, mediastinum, brain and spine, liver, and rarely adrenal glands. (1) Only 18 cases of adult primary adrenal teratomas have been reported since 1952. (2)Clinical Case: A 48-year-old woman with 4 days of worsening abdominal pain underwent CT imaging, which demonstrated a 6cm complex left adrenal mass containing peripheral and scattered internal-coarse calcifications with internal soft tissue and fat components, suggestive of adrenal myelolipoma with probable sequela of previous hemorrhage. Subsequent endocrine follow-up ruled out a cortisol secreting tumor with a negative dexamethasone suppression test and pheochromocytoma with normal serum free metanephrines and normetanephrines. Dedicated adrenal protocol CT scan further characterized the mass as a mature adrenal teratoma containing a rudimentary mandible and two teeth within the soft tissue associated with internal microscopic fat. The left renal vein was anteriorly displaced by this left adrenal mass and severely narrowed by the large adrenal mass, with development of left retroperitoneal collateral venous drainage from the left kidney into the lumbar venous system. The patient opted for conservative management with active clinical surveillance. Conclusion: This is a rare case of adrenal mature teratoma in an adult, originally diagnosed as an adrenal myelolipoma. This case highlights the use of more dedicated adrenal imaging for the characterization of adrenal tumors and the broad differential of benign non-functional adrenal tumors, including myelolipomas, lipomas, angiomyolipomas, and nonfunctional adenomas. However, a definitive diagnosis can only be confirmed by surgical removal of the tumor, usually through a laparoscopic approach, with histopathologic evaluation. References: (1) O’Donovan EJ, Thway K, Moskovic EC. Extragonadal teratomas of the adult abdomen and pelvis: a pictorial review. Br J Radiol. 2014;87(1041):20140116. doi:10.1259/bjr.20140116(2) Zhou L, Pan X, He T, et al. Primary adrenal teratoma: A case series and review of the literature. Mol Clin Oncol. 2018;9(4):437-442. doi:10.3892/mco.2018.1687 Presentation: 6/1/2024