Medullary thyroid cancer secreting carbohydrate antigen 19-9 (Ca 19-9): a fatal case report.

Background: During follow-up for patients with medullary thyroid cancer (MTC), the levels of serum calcitonin and carcinoembryonic antigen are important, and the doubling time of these biomarkers significantly correlates with disease progression. Other antigens are present in tumor tissue and the sera of patients with MTC, but there are scarce published data on the serum levels of carbohydrate antigen 19-9 (Ca 19-9), a tumor marker primarily used for the diagnosis and follow-up of pancreatic and gastrointestinal neoplasias. Recently, the case of a 56-year-old woman with multiple endocrine neoplasia type 2B with high serum levels of Ca 19-9 was reported; this patient experienced rapid disease progression that led to her death.