Cellular Adenomatous Nodule

Aspirates of thyroid nodules composed of follicular cells arranged in a predominantly macrofollicular pattern and lacking nuclear features of PTC are benign, and we diagnose them as adenomatous nodules (Figures 6.2-6.9). A variety of Figure 6.2. Adenomatous nodule. These nodules are characterized by a predominance of macrofollicles such as the one shown here. During smear preparation, watery colloid is extruded from the macrofollicle into the background. (Smear, Papanicolaou.) Figure 6.2....

Chronic Lymphocytic Thyroiditis Hashimotos Thyroiditis

Aspirates are variably cellular depending upon the degree of fibrosis of the thyroid gland, and in the small subset of cases of the fibrosing variant of Hashimoto's thyroiditis, the specimen is hypocellular. Aspirates of chronic lymphocytic thyroiditis are characterized by a combination of two features (1) a mixed population of lymphocytes, plasma cells, and lymphohistio-cytic aggregates, and (2) occasional cohesive clusters of follic-ular cells with oncocytic features (Hurthle cells) (Figures...

Suspicious for a Follicular Neoplasm

The group of aspirates diagnosed as suspicious for a follicular neoplasm includes both follicular adenomas and FC. Aspirates are cellular and are characterized by follicular cells arranged in any of three patterns microfollicles, trabeculae, or crowded three-dimensional groups (Figures 6.14, 6.15, 6.16). Aspirates with a combination of these patterns can also be seen. This approach to diagnosing follicular lesions works because FCs are virtually never predominantly composed of normal-sized...

Differential Diagnosis and Pitfalls

Colloid Parathyroid Adenoma

Problems may arise in diagnosing adenomatous nodules when they are cellular, but careful attention to the macrofol-licular arrangement of cells will avoid calling the aspirate a follicular neoplasm. As alluded to previously, a variety of changes including Hurthle cells, mild nuclear atypia, meta-plastic squamous cells, or spindle-shaped cells can be seen in aspirates of adenomatous nodules. In particular, the presence of spindle cells and metaplastic squamous cells can raise the possibility of...

Subacute Thyroiditis

Aspirates of subacute thyroiditis are usually hypocellular and consist of multinucleated giant cells that surround and engulf colloid. In addition, loose aggregates of epithelioid histiocytes (granulomas) are characteristic (Figures 4.7,4.8). Care should be taken not to misinterpret the epithelioid histiocytes with their curved nuclei and abundant granular cytoplasm as an epithelial neoplasm. A variable amount of background mixed inflammatory cells including lymphocytes, plasma cells,...

Graves Disease

Graves' disease (diffuse toxic goiter) is a diffuse hyperplastic autoimmune thyroid disorder of middle-aged women who typically present with hyperthyroidism. It is usually diagnosed clinically, and thus is seldom sampled by FNA except when a dominant cold nodule is present. Aspirates are hypercellular and contain follicular cells in large branching sheets as well as in microfollicles in a background of abundant pale watery colloid (Figures 6.11, 6.12). Follicular cells have moderate amounts of...

Nuclear Grooves and Pseudoinclusions

The presence of extensive nuclear grooves is a common finding in PTC, caused by an infolding of the nuclear membrane. Nuclear grooves are present in nearly all cases of PTC, but they may be sparse in up to 25 of cases. They are often parallel to the long axis of the oval nuclei, giving a coffee bean appearance (see Figure 9.5). Nuclear grooves alone are nonspecific and can be seen in a variety of neoplastic and non-neoplastic cells, including macrophages and benign follicular cells. However,...

Branchial Cleft Cysts and Ultimobranchial Body Cysts

Ultimobranchial Cyst

Branchial cleft-like cysts lymphoepithelial cysts and ulti-mobranchial body cysts cystic solid cell nests are rare in the thyroid gland, and when they do occur it is often in association with Hashimoto's thyroiditis. Aspirates of branchial cleft cysts of the neck and branchial cleft-like cysts of the thyroid are similar and contain turbid proteinaceous fluid and degenerate squamous cells, as well as glandular cells that may be mucin containing or ciliated.Variable amounts of background...