Shubo Wang ^*

• The Affiliated Weihai Second Municipal Hospital, Weihai, China

Background: Human chorionic gonadotropin (hCG), a glycoprotein hormone, is widely used in clinical settings for pregnancy detection and as a sensitive marker for trophoblastic tumors.While primarily associated with placental trophoblasts, this hormone is also naturally expressed at low levels in other organs and can be elevated in nontrophoblastic malignancies.Recent studies have indicated that high β-hCG levels in nontrophoblastic tumors may signify aggressive disease and correlate with a poor prognosis.Case presentation: This report presents a rare case of a 44-year-old perimenopausal woman being diagnosed with rectal cancer through investigations of atypical complaints. Over a period spanning from the onset of left lower abdominal pain to the presentation in the office, the patient had been seen in the emergency department (ED) three times and in outpatient gynecological acute visits two times for intermittent left lower quadrant (LLQ) pain. At these points of care, the β -hCG level was elevated at 10.27 mIu/mL (<5 mIU/mL) and continued to increase. Next, she was diagnosed with presumed ectopic pregnancy and treated with methotrexate, which did not yield the expected decrease in β-hCG. The transvaginal ultrasound scan found an irregular mass of about 17×10mm on the inner side of the left ovary, with an indistinct boundary. Diagnostic curettage did not reveal evidence of pregnancy or endometrial disease. Upon current presentation to the outpatient gynecology clinic, she suffered from persistent pain of LLQ and menorrhagia lasting 54 days. Further testing to locate the source of β-hCG included a colonoscopy which identified an ulcerated irregular mass between 9 and 18cm from the anus. Based on pathology results, the ultimate etiology of elevated β-hCG was secretion by neuroendocrine rectal carcinoma. Initially, the patient's metastatic disease was responsive to chemotherapy at multiple locations, but the patient passed due to brain metastases two years later.