A case report of paraneoplastic syndrome in β-hCG-secreting duodenal adenocarcinoma

Elevations in serum beta-human chorionic gonadotropin (β-hCG) are usually found in pregnancy or pregnancy-related conditions such as gestational trophoblastic tumors. However, β-hCG can also be produced in the stomach, colon, liver, and lung in small amounts (1). Malignancies in these organs can consequently result in increased serum levels of β-hCG, which is typically a sign of aggressive disease and poor prognosis (2). We report a case of a 50-year-old female newly diagnosed with stage IV duodenal adenocarcinoma with metastasis to the lungs, liver, lymph nodes, and left adrenal gland. Her pregnancy test was initially negative but later in her course changed to positive. Workup including pelvic ultrasound was unrevealing, making intrauterine and ectopic pregnancy unlikely. Her elevated β-hCG was consistent with a paraneoplastic syndrome originating from malignancy of the duodenum, which has not been previously reported on review of literature