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 […]
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 […]
Adequacy of the specimen
Specimens may be unsatisfactory due to obscuring blood, overly thick smears, air-drying of alcohol-fixed smears or an inadequate number of follicular cells. Specimens containing at least five groups of follicular cells, each composed of at least ten cells, are considered satisfactory for evaluation. With experience, the average unsatisfactory rate is about 5% to 10%. It […]
Riedel`s disease
Riedel`s disease This rare disease is characterized by a dense fibrosis which replaces the parenchyma of the thyroid and extends to the surrounding structures, resulting in a hard mass in the neck which clinically mimics a carcinoma. The aspiration usually results in a dry tap because of the dense fibrosis.
Parathyroid tumours
Parathyroid adenomas and the rare parathyroid carcinoma can be clinically mistaken for thyroid nodules. Smears are cellular, with cohesive sheets, ribbon-like cords and occasional microacini. The cells have round nuclei with a coarsely granular chromatin pattern and granular cytoplasm. Bare nuclei and isolated cells can be present. Slight and focal nuclear pleomorphism can be seen. […]
Evaluation of the specimen
Several features will be considered in the evaluation of the specimen: the type of cells (such as thyrocytes, macrophages, lymphocytes) Thyrocytes and macrophages. Fluid colloid in the background, bland thyrocytes and pigmented macrophages. Lymphocytes and thyrocytes. A group of bland thyroid cells showing a follicular arrangement, surrounded by smaller lymphoid cells with little amount of identifiable cytoplasm. […]
Multinodular goitre
It is a nodular enlargement of the gland, due to derangements in hormone production, which is often asymmetric and sometimes extreme. Follicular cells undergo hyperplasia, leading to the formation of several nodules. The nodules, which are usually not encapsulated, may considerably vary in their microscopic appearance: some of them are composed of very large macrofollicles […]