Medullary Thyroid Carcinoma

and Zdeněk Fryšák1



(1)
Department of Internal Medicine III – Nephrology, Rheumatology and Endocrinology, Faculty of Medicine and Dentistry, Palacky University Olomouc and University Hospital Olomouc, Olomouc, Czech Republic

 



Keywords
Medullary thyroid carcinomaSerum calcitoninCalcificationsLymph node metastases



16.1 Essential Facts






  • Medullary thyroid carcinoma (MTC) constitutes approximately 2–5% of all thyroid malignancies, but it is responsible for up to 13.4% of all deaths from thyroid cancer. The prevalence is about the same in both males and females [1].


  • It is a well-differentiated type of tumor that arises from the parafollicular (C cells) of the thyroid gland, and is categorized as a neuroendocrine tumor [1].


  • The parafollicular cells secrete calcitonin. Serum calcitonin is greatly elevated in almost all patients with MTC. There appears to be a direct correlation of calcitonin level and the extent of thyroid involvement by MTC.


  • In 80% of patients MTC occurs sporadically, as a result of a mutation involving only the somatic cells. Sporadic forms of MTC are more common in older patients (mean age at presentation about 47 years) [1].


  • About 20% of patients have familial MTC, caused by germline mutation in the RET protooncogene. The hereditary forms of MTC are more common in younger patients.


  • MTC is considered to be less aggressive than ATC, but more lethal than PTC and FTC.


  • While most patients with MTC typically present with a palpable nodule in the upper part of the thyroid lobe, some patients may present with systemic symptoms associated with distant metastases [1].


  • The clinical course of both forms of MTC is described in retrospective review of 104 patients by Kebebew; 56% of patients had sporadic MTC, 22% had familial MTC, 15% had MEN 2A, and 7% had MEN 2B [2]:



    • 32% of the patients with hereditary MTC were diagnosed by screening (genetic and/or biochemical). These patients had a lower incidence of cervical lymph node metastasis and 94.7% were cured at last follow-up compared with patients not screened.


    • Patients with sporadic MTC who had systemic symptoms (diarrhea, bone pain, or flushing) had widely metastatic MTC and 33.3% of those patients died within 5 years.


    • Overall, 49.4% of the patients were cured. In addition, 12.3% had recurrent MTC and 38.3% had persistent MTC. Patients with persistent or recurrent MTC who died of MTC lived for an average of 3.6 years.


    • Screening for MTC and early treatment (total thyroidectomy with central neck lymph node clearance) had a nearly 100% cure rate.


  • Five-year recurrence-free survival varies from 20 to 73% and is related to the number of metastatic LN (Fig. 16.3hh) and postoperative calcitonin and CEA doubling times [3].


16.2 US Features of Medullary Thyroid Carcinoma




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Jul 15, 2017 | Posted by in ULTRASONOGRAPHY | Comments Off on Medullary Thyroid Carcinoma

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