Beyond the Recommendations of the Clinical Guidelines for Medullary Thyroid Cancer - A Case Report.

Abstract

Medullary thyroid cancer (MTC) is a rare disease from parafollicular C cells. Calcitonin has been suggested as a screening; its levels are proportional to the tumor size and predictive of metastatic disease. We present a case where an early action was taken with lower cut-off points. Male patient, 49 years old. Thyroid ultrasound (US) with a suspicious nodule. Fine Needle Aspiration Biopsy (FNAB) suggests MTC, with pre-operative serum calcitonin (CTN) of 591 pg/mL. Total thyroidectomy with central and bilateral dissection was performed. Biopsy: MTC in left nodule of 26 mm without lymph nodes (LN) metastases. Follow-up with undetectable CTN for six years. After that, CT was 4.7 pg/mL, and carcinoembryonic antigen (CEA) was 1.2 ng/mL. Neck US showed bilateral LN. FNAB of LN does not show recurrence. A progressive rise of markers with doubling time of CTN and CEA was 16 and 51.3 months, respectively. CTN raised until 112 pg/mL. Given the lack of cervical compromise, a neck and lung CT, liver MRI, and bone scintigraphy were ordered despite CTN levels < 150 pg/mL. MRI showed hypervascular hepatic lesions, contrasted with gadoxetic acid. PET Ga68-DOTATATE showed lesions with overexpression of somatostatin receptors in the liver. Surgery was done, and a biopsy confirmed metastases. Conclusions: The clinical guidelines may allow the management of cases; however, they should be used considering each case context. In our patient, if the guidelines had been strictly followed, it would not have been possible to detect liver metastases to achieve a surgical resection with curative intent.