Thyroid Cytology

Question 1

Adequacy criteria for a thyroid cytology specimen

Answer 1

At least 6 groups of at least 10 follicular cells that are well visualized.

Exceptions:
Abundant colloid is compatible with a colloid nodule.
Abundant inflammation with a solid nodule.
Atypia.

Question 2

Answer 2

Lymphocytic thyroiditis

Unless. . . you see a granuloma. This makes it De Quervain’s thyroiditis.

Question 3

Answer 3

Papillary thyroid carcinoma

Papillary nuclear features, powdery, pale cytoplasm with marginal micronucleoli, and dense, squamoid cytoplasm.

Papillary structures may or may not be seen.

Question 4

Answer 4

Follicular neoplasm / suspicious for follicular neoplasm

Made up of microfollicles: less than 15 cells
arranged in a circle that is at least 2/3 complete.

NOTE: Cytology CANNOT differentiate between follicular adenomas and follicular carcinomas. These diagnoses require architectural features BY DEFINITION.

Question 5

Answer 5

Medullary thyroid carcinoma

Discohesive, plasmacytoid, polygonal-to-spindled cells with salt and pepper chromatin. Granular cytoplasm. Mild to moderate pleomorphism. Occasional intranuclear pseudoinclusions may be seen.

Amyloid fragments may also be present.

Question 6

Bethesda classification system for thyroid cytologic specimens

Answer 6