with
papillary thyroid carcinoma After a
thyroid nodule is found during a physical examination or incidentially on imaging, a referral to an
endocrinologist or a
thyroidologist may occur. Most commonly, an
ultrasound is performed to confirm the presence of a nodule and assess the status of the whole gland. Various radiological clinical criteria, including the thyroid imaging reporting and data system (TI-RADs) score, are used to characterize the risk of malignancy. TI-RADS developed by the
American College of Radiology (ACR) guides clinicians in deciding which nodules require fine-needle aspiration cytology (FNAC) and in planning follow-up. Various online tools have been developed to assist in applying these criteria to clinical practice. On ultrasound, nodules that are hypoechogenic (solid consistency), having irregular borders, increased vascularity, calcifications, or being taller than wide on transverse views are associated with malignancy. A thyroid scan, performed often in conjunction with a radioactive iodine uptake test may be used to determine whether a nodule is hyperactive which may help to make a decision whether to perform a biopsy of the nodule. Measurement of
calcitonin is necessary to exclude the presence of
medullary thyroid cancer. To achieve a definitive diagnosis, a
fine needle aspiration cytology test may be performed and reported according to the
Bethesda system. After diagnosis, to understand potential for spread of disease, or for follow up monitoring after surgery, a whole body I-131 or I-123 radioactive iodine scan may be performed. In adults without symptoms, screening for thyroid cancer is not recommended.
Classification Thyroid cancers can be classified according to their
histopathological characteristics. These variants can be distinguished (distribution over various subtypes may show regional variation): •
Papillary thyroid cancer (75 to 85% of cases) – is more often diagnosed in young females compared to other types of thyroid cancer and has an excellent prognosis. It may occur in women with
familial adenomatous polyposis and in patients with
Cowden syndrome. A follicular variant of papillary thyroid cancer also exists. • Newly reclassified variant:
noninvasive follicular thyroid neoplasm with papillary-like nuclear features is considered an indolent tumor of limited biologic potential. •
Follicular thyroid cancer (10 to 20% of cases •
Medullary thyroid cancer (5 •
Poorly differentiated thyroid cancer •
Anaplastic thyroid cancer (1 to 2%) despite constituting only 1% of thyroid cancers, the type is responsible for 20% of thyroid cancer deaths. These types have a more favorable prognosis than the medullary and undifferentiated types. • Papillary microcarcinoma is a subset of papillary thyroid cancer defined as a nodule measuring less than or equal to 1 cm. 43% of all thyroid cancers and 50% of new cases of papillary thyroid carcinoma are papillary microcarcinoma. Management strategies for incidental papillary microcarcinoma on ultrasound (and confirmed on FNAB) range from total thyroidectomy with radioactive iodine ablation to lobectomy or observation alone. Harach et al. suggest using the term "occult papillary tumor" to avoid giving patients distress over having cancer. Woolner
et al. first arbitrarily coined the term "occult papillary carcinoma", in 1960, to describe papillary carcinomas ≤ 1.5 cm in diameter.
Staging Cancer staging is the process of determining the extent of the development of a cancer. The
TNM staging system is usually used to classify stages of cancers, but not of the brain. The TNM system is broken into three key factors. The T part stands for the size of the tumor, and has it grown into any other body part near the body. The N is for if the cancer has grown into any lymph nodes nearby. And finally, the M stands for if the cancer has metastasized, and if the cancer has spread to any major organs in the body. After the TNM system has been determined, the number system is then used to describe the severity of the cancer. The stages range from one (I) to four (IV), typically with stage one being the lowest and least amount of cancer spread, and stage four being the highest with the most amount of cancer spread through the body. Thyroid cancer staging can be determined by either clinical staging which includes several different tests evaluate the extent of the cancer, or pathological staging which includes surgery. Scintigraphy, also known as iodine-131 scan, is a noninvasive imaging test that uses small amounts of radioactive material to check how the thyroid is working. The thyroid cells (both normal and cancerous) easily absorb the iodine and when shown through imaging the scintigraphy scan will detect the radiation emitted by the iodine-131, so if the cancer has spread/metastasized to other parts of the body, they may also absorb the iodine which will show up as hot spots on the scan. Most patients with thyroid cancer usually have it contained within the thyroid when they are diagnosed. Usually 30% will have metastatic cancer, with the cancer usually being spread to the lymph nodes in the neck. Most patients with thyroid cancer have good chances of survival, but that changes if the cancer is spread outside of the neck at the time of the diagnosis. While death is rare in cases of thyroid cancer, it significantly increases when the cancer has spread to outside of the neck such as the lungs and bones. Only about 1-4% of the patients have a chance of this kind of metastatic cancer. ==Treatment==