Abstract
BACKGROUND: Malignancies of the adrenal gland account for a minority of adrenal incidentalomas, with metastases being more common than primary tumors. Cholangiocarcinoma, an aggressive malignancy of the bile ducts, rarely metastasizes to the adrenal gland, and to date, no cases of primary cholangiocarcinoma originating in the adrenal gland have been reported. This case presents a novel and unprecedented tumor origin, offering valuable insights into diagnostic challenges and the utility of molecular profiling in rare adrenal neoplasms. CASE PRESENTATION: A 44-year-old female with a history of hypertension, obstructive sleep apnea, and bariatric surgery presented with progressive voiding dysfunction. Imaging revealed a right adrenal mass with radiologic features suspicious of adrenocortical carcinoma. Biochemical evaluation for a functional tumor was unremarkable. She underwent laparoscopic adrenalectomy. Histopathology revealed metastatic adenocarcinoma with an immunoprofile initially suggestive of a pancreatic primary. However, further molecular analysis using AI-driven genomic profiling indicated a 91% probability of cholangiocarcinoma. Despite comprehensive post-operative imaging, including PET-CT and MRCP, no primary hepatic, pancreatic, or biliary tumor was identified, supporting the diagnosis of a primary adrenal cholangiocarcinoma. The patient was treated with six cycles of gemcitabine, cisplatin, and durvalumab, which was later discontinued due to thyroiditis. Follow-up imaging revealed no residual or metastatic disease. CONCLUSIONS: This case represents the first known report of cholangiocarcinoma arising in the adrenal gland, broadening the differential diagnosis for adrenal incidentalomas. It underscores the critical role of advanced histopathologic and genomic profiling in evaluating atypical adrenal lesions, especially in patients without a known primary malignancy. Comprehensive diagnostic workup and a multidisciplinary approach are essential for accurate diagnosis and appropriate management of rare adrenal tumors.