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.	Lymphocytes and thyrocytes.

•amount and type of colloid (scanty-abundant, fluid-dense)

Colloid.

•cellularity (scanty, moderate, marked)

Highly cellular smear showing a microbiopsy.	Less cellular but diagnostic smear.

•architecture (monolayers, crowded clusters, sheets, macro/microfollicles, papillary clusters, isolated cells)

Sheets of bland thyroid cells.		Thyroid cells in a microfollicular arrangement.	A papillary cluster.

•presence of bare nuclei

Bare nuclei.

•cytologic features (cytoplasm, nuclei)

In neoplastic lesions the specimens are usually highly cellular. Flat sheets are common in goitre and macrofollicular adenomas, but can also be present in carcinomas. Macrofollicles are usually associated with multinodular goitre and macrofollicular adenomas. A predominance of microfollicles can be suggestive of a follicular neoplasm. Papillary clusters, with cells lining a fibrovascular core, are characteristic of papillary carcinoma. Smears with a high ratio of colloid to follicular cells usually indicate a benign nodule.

Cytologic features:

• cytoplasm (amount, staining)
• chromatin pattern
• nuclear membrane (smooth or irregular)
• nuclear groovings and pseudoinclusions

Abundant cytoplasm containing granules.	Nuclear pseudoinclusions and groovings.