Medullary carcinoma
Medullary thyroid carcinoma (MTC) accounts for about 5% of thyroid cancers. Differently from the other carcinomas, which arise from the follicular cells, medullary carcinoma arises from parafollicular cells (C cells) of the thyroid, which synthetize calcitonin. About 80-90% are sporadic and occur in adults, the rest occur in children in genetic syndromes called multiple endocrine […]
Insular carcinoma
Poorly differentiated carcinomas (insular carcinoma) Some thyroid carcinomas have an intermediate grade of atypia between well-differentiated carcinomas and anaplastic carcinoma. These poorly differentiated carcinomas account for <5% of thyroid carcinomas. One distinctive form is insular carcinoma. Cytologic diagnostic features high cellularity mostly single cells clusters, microfollicles monomorphous round nuclei On hystologic preparations, malignant cells of […]
Anaplastic carcinoma
It accounts for less than 5% of thyroid cancers and it is associated with a very poor prognosis. It presents clinically as a rapidly growing neck mass which usually has already infiltrated adjacent structures at the time of diagnosis. In about one-third of cases, anaplastic carcinoma is associated to a well-differentiated thyroid carcinoma (such as […]
Lymphoma
Primary thyroid non-Hodgkin lymphoma (PTNHL) is a rare neoplasm, which typically occurs in older-aged women in the setting of Hashimoto`s thyroiditis. The risk for a patient with thyroditis is much greater than in the general population, but occurrence of a lymphoma is very rare. Most patients present with an enlarging neck mass and cervical lymph […]
Metastatic carcinoma
The breast, the kidney and the lungs are the most common primary sites of metastatic tumors to the thyroid. This possibility should be considered if the cytologic pattern does not conform with common neoplasms or the patient has a history of cancer elsewhere. In many cases, however, there is no clinical history of malignancy. Metastatic […]
Papillary carcinoma
Papillary thyroid carcinoma (PTC) is the most common malignancy of the thyroid (>80% of thyroid cancers). It may occur at any age, but most patients are between 30 and 50 years old; most of them are female (F:M 3:1). It usually presents as a solitary, non-functioning (‘cold’) nodule, sometimes with cervical lymphadenopathy due to metastatization. […]
Terminology for reporting results
Terminology for reporting results It is advisable to use diagnostic categories such as negative (benign), suspicious, positive (malignant) and non-diagnostic (unsatisfactory), followed by a description. Negative (benign) aspirate Positive (malignant) aspirate Suspicious aspirate An increasingly used classification identifies five categories basically splitting the suspicious category into probably reactive (T3 – low risk of malignancy) and […]
Radiation changes
Long-term morphologic changes may occur in the thyroid of patients who undergo external irradiation of the neck (usually as a therapy of malignancies) or administration of radioactive iodine (which is used to treat hyperthyroidism). Cytologic diagnostic features sheets (macrofollicles) enlarged cells normal N/C ratio Hürthle cell change cytoplasmic vacuolization marked nuclear atypia: marked size variation […]
Negative (benign) aspirate
This category accounts for the vast majority of FNA aspirates, proportions from different series ranging from 50-75%. Between 60-85% of negative aspirates are obtained from either dominant nodules within nodular hyperplasia or dominant nodules of non-toxic goitre. The remainder of negative specimens are obtained from other benign lesions, such as cysts, inflammatory lesions (e.g. thyroiditis), […]
The follicular lesions
The follicular lesions The follicular lesions include follicular adenoma and follicular carcinoma. Papillary carcinoma also derives from follicular cells, but it is distinguished from the other lesions by its characteristic nuclear features. While for some conditions, such as Hashimoto`s thyroiditis and papillary carcinoma, FNA can be diagnostic, for the follicular lesions it represents a screening […]