A team of researchers from Italy reported the case of a young man with serum calcitonin-negative medullary thyroid carcinoma (MTC) that metastasized to the lateral cervical node. This case illustrates the fact that normal serum levels of calcitonin cannot exclude MTC and that this type of cancer is difficult to diagnose.

“The current lack of an optimal strategy for the diagnosis and postoperative follow-up for patients with negative serum calcitonin tumor presents a diagnostic challenge for physicians,” the authors of the study wrote.

Serum calcitonin levels are normally strictly associated with the size of the tumor and the presence of metastases in MTC. However, there have been 47 cases of serum calcitonin-negative MTC reported in the literature. The behavior of these cancers ranged from nonaggressive to aggressive. 

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In the case reported here, doctors initially failed to diagnose the patient due to normal serum calcitonin levels and the absence of large nodules in the thyroid. However, upon examination of the neck biopsy of a lateral cervical mass, the patient was diagnosed with MTC. 

Read more about the diagnosis of MTC

The patient underwent total thyroidectomy and cervical lymphadenectomy to treat his disease. During follow-up, an ¹⁸F-DOPA positron emission tomography (PET) scan was performed since serum markers were not useful and carcinoembryonic antigen levels were negative. 

The researchers reported that there was no evidence of disease relapse after 3 years of follow-up.

The study is published in the American Journal of Case Reports.

MTC is a rare type of thyroid cancer arising from the parafollicular cells. Malignant parafollicular cells normally secrete high levels of calcitonin and carcinoembryonic antigen, which are widely used to diagnose the disease. Early diagnosis is of utmost importance, as the best therapeutic approach and patient outcomes depend on the diagnosis. 


Licata L, Di Fidio CA, Vacante M, et al. A rare case of negative serum calcitonin in metastatic medullary thyroid carcinoma: diagnosis, treatment, and follow-up strategy. Am J Case Rep. Published online August 11, 2022. doi:10.12659/AJCR.935207