The term endocrine cancers most commonly refers to cancers of the thyroid, parathyroid, adrenal glands, and endocrine tumors arising in the pancreas and intestinal tract. Most lesions in these glands are benign, but both benign and malignant endocrine tumors can be associated with multiple neoplasia syndromes. This chapter will discuss benign and malignant endocrine neoplasms and the genetic underpinnings of each.
NON-MEDULLARY THYROID CANCER
Risk Assessment and Management
Most thyroid cancers present as new thyroid nodules that are discovered by patients or clinicians by physical exam or incidentally on imaging. It is important to note that most thyroid nodules discovered in the general population are benign—only 5 to 10% are malignant. Risk factors for any form of thyroid malignancy include radiation exposure (especially in childhood), extreme age ranges (children or elderly), female sex, and family history.1–3
While most non-medullary thyroid cancers (NMTC) are sporadic, 3 to 9% of cases present in familial clusters with at least two first-degree relatives also with this cancer.4 Individuals with one or more first-degree relatives with NMTC will have a 4- to 10-fold increase in their own risk for the disease.5 Therefore, it is essential to obtain detailed personal and family histories upon discovery of a new thyroid nodule. A history of rapid increase in size, dyspnea, dysphagia, hoarseness. and new onset of Horner’s syndrome all suggest the possibility of cancer. A focused physical exam should evaluate the entirety of the neck and note the size, firmness, and mobility of the nodule, and features such as lymphadenopathy or adherence to neighboring structures increase the suspicion for malignancy.1–3
The next step in workup is to perform thyroid function testing and focused thyroid ultrasound. Thyroid ultrasound is a sensitive and specific imaging modality for thyroid nodules and can provide helpful clues as to the nature of the lesion, such as size, internal calcifications, solid versus cystic components, associated lymphadenopathy, and even local invasion. It should always be performed when a thyroid nodule or goiter is identified, even if the patient has already had other neck imaging studies (CT, MRI, etc.).1–3
Thyroid function tests have utility in determining the functional status of a thyroid nodule. If the TSH level is suppressed and ultrasound demonstrates a single nodule with no other concerning findings, the most likely diagnosis is an autonomously functioning thyroid nodule. Also termed “hot nodules,” they are rarely malignant and can be safely observed with repeat imaging to confirm that they remain stable in size. They should not undergo fine-needle aspiration (FNA) as the results are often misleading and do not alter the management strategy. Occasionally, it can be unclear if a thyroid nodule is “hot” or “cold” when the TSH level is borderline low or when there are multiple nodules on imaging.1–3
FNA should be performed ...