Functional bowel disease symptoms and a de novo raised carcinoembryonic antigen: delayed diagnosis of medullary cell thyroid carcinoma

Carcinoembryonic antigen (CEA) is commonly raised in patients with colorectal carcinoma (CRC) and has an established role in postoperative monitoring to detect early recurrence. CEA is not recommended as a screening tool for CRC; however, a de novo raised level mandates further investigation with a colonoscopy. This report describes a patient referred from primary care with a raised CEA and functional bowel symptomatology who went on to have a normal colonoscopy. The persistently rising CEA prompted a repeat colonoscopy, upper gastrointestinal and small bowel investigation and a CT of the abdomen and pelvis, without any cause being found. Finally, a CT-positron emission tomography scan revealed localised uptake in the thyroid gland, with a fine-needle aspiration confirming a diagnosis of medullary cell thyroid carcinoma with regional lymph node involvement.