Endocrine Abstracts

Serum CA 19-9 (carbohydrate antigen 19-9) is a tumor marker of monosialoganglioside structure. Its level is frequently measured for screening purposes in daily practice by physicians, while its main use is in the study of tumor recurrence and follow-up of recurrences. Although significant elevations in CA 19-9 levels cause suspicion of malignancy, an underlying malignant disease may not always be determined and benign pathologies may also be seen. A 45-year-old female patient being followed for Hashimoto’s thyroiditis applied to our clinic with complaints of fatigue, tiredness, and hair loss. Elevations of both thyroid-stimulating hormone (TSH) and CA 19-9 were seen. Normal TSH and CA 19-9 levels were observed after the patient was treated for hypothyroidism, and analysis results were determined to be normal after testing for malignancy. Based on our case, we think that hypothyroidism should be kept in mind in patients with CA 19-9 elevation while making a differential diagnosis.