Medullary thyroid cancer overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ammu Susheela, M.D. [2]
Overview
Medullary thyroid cancer was first discovered by John Beach Hazard, an American pathologist, in 1959.[1] Medullary thyroid cancer may be classified according to mode of occurrence into 2 groups: sporadic medullary thyroid cancer and inherited medullary thyroid cancer. The development of medullary thyroid cancer is the result of genetic mutation of RET proto-oncogene. On gross pathology, well circumscribed, gray, white, or yellow in color mass is a characteristic finding of medullary thyroid cancer. On microscopic histopathological analysis, polygonal to the spindle to small cells, interstitial edema, and vascular hyalinized stroma are characteristic findings of medullary thyroid cancer. Medullary thyroid cancer is caused by a mutation in the RET proto-oncogene. If left untreated, patients with medullary thyroid cancer may progress to develop metastasis. Common complications of medullary thyroid cancer include vocal cord compression, dysphagia, and dyspnea. The presence of metastasis is associated with a particularly poor prognosis among patients with medullary thyroid cancer. The 5-year event free survival rate is 80%. The hallmark of medullary thyroid cancer is lump in the neck. A positive family history of medullary thyroid cancer or multiple endocrine neoplasia is suggestive of medullary thyroid cancer. The most common symptoms of medullary thyroid cancer include diarrhea, flushing, and dysphagia. Laboratory findings consistent with the diagnosis of medullary thyroid cancer include decreased thyroid stimulating hormone, elevated calcitonin, and decreased calcium. Surgery is the mainstay of treatment for medullary thyroid carcinoma.
Historical Perspective
Medullary thyroid cancer was first discovered by John Beach Hazard, an American pathologist, in 1959.[1]
Classification
Medullary thyroid cancer may be classified according to the mode of occurrence into 2 groups: sporadic medullary thyroid cancer and inherited medullary thyroid cancer.
Pathophysiology
The development of medullary thyroid cancer is the result of genetic mutation of RET proto-oncogene. On gross pathology, well circumscribed, gray, white, or yellow color mass is a characteristic finding of medullary thyroid cancer. On microscopic histopathological analysis, polygonal to the spindle to small cells, interstitial edema, and vascular hyalinized stroma are characteristic findings of medullary thyroid cancer.
Causes
Medullary thyroid cancer is caused by a mutation in the RET proto-oncogene.
Differential Diagnosis
Medullary thyroid cancer must be differentiated from anaplastic thyroid carcinoma, papillary thyroid carcinoma, and Hurthle cell carcinoma.
Epidemiology and Demographics
The incidence of medullary thyroid cancer is approximately 1000 per 100,000 individuals in the United States per year. The incidence of medullary thyroid cancer increases with age; the median age at diagnosis peaks in the 3rd to 4th decades.
Risk Factors
Common risk factors in the development of medullary thyroid cancer are a family history of medullary thyroid cancer and a family history of multiple endocrine neoplasia.
Screening
According to the American Society of Clinical Oncology, screening for medullary thyroid cancer by RET gene testing is recommended for children with an increased risk of medullary thyroid cancer.
Natural history, Complications and Prognosis
If left untreated, patients with medullary thyroid cancer may progress to develop metastasis. Common complications of medullary thyroid cancer include vocal cord compression, dysphagia, and dyspnea. The presence of metastasis is associated with a particularly poor prognosis among patients with medullary thyroid cancer. The 5-year event-free survival rate is 80%.
Staging
According to the American Joint Committee on Cancer (AJCC)[2] there are 4 stages of medullary thyroid cancer based on the clinical features and findings on imaging. Each stage is assigned a letter and a number that designates the tumor size, number of involved lymph node regions, and metastasis.
History and Symptoms
The hallmark of medullary thyroid cancer is lump in the neck. A positive family history of medullary thyroid cancer or multiple endocrine neoplasia is suggestive of medullary thyroid cancer. The most common symptoms of medullary thyroid cancer include diarrhea, flushing, and dysphagia.
Physical Examination
Patients with medullary thyroid cancer usually appear thin and cachexic. Physical examination of patients with medullary thyroid cancer is usually remarkable for thyromegaly, lymphadenopathy and anxiety.
Laboratory Findings
Laboratory findings consistent with the diagnosis of medullary thyroid cancer include decreased thyroid stimulating hormone, elevated calcitonin, and decreased calcium.
CT
CT scan may be helpful in the diagnosis of medullary thyroid cancer.
Echocardiography or Ultrasound
Neck ultrasound may be performed to detect medullary thyroid cancer.
Other Diagnostic Studies
Other diagnostic studies for medullary thyroid cancer include nuclear imaging, which demonstrates increased uptake of radioactive iodine in the areas of metastases.
Medical Therapy
The predominant therapy for medullary thyroid cancer is surgical resection. Adjunctive chemoradiation may be required. The optimal therapy for medullary thyroid cancer depends on the stage at diagnosis.
Surgery
Surgery is the mainstay of treatment for medullary thyroid carcinoma.
Primary Prevention
There are no established measures for the primary prevention of medullary thyroid cancer.
Secondary Prevention
There are no established measures for the secondary prevention of medullary thyroid cancer.
Reference
- ↑ 1.0 1.1 HAZARD JB, HAWK WA, CRILE G (1959). "Medullary (solid) carcinoma of the thyroid; a clinicopathologic entity". J. Clin. Endocrinol. Metab. 19 (1): 152–61. doi:10.1210/jcem-19-1-152. PMID 13620740.
- ↑ Stage Information for Thyroid Cancer Cancer.gov (2015). http://www.cancer.gov/types/thyroid/hp/thyroid-treatment-pdq#link/stoc_h2_2- Accessed on October, 29 2015