Three-dimensional cytomorphology in fine needle aspiration biopsy of subacute thyroiditis.

OBJECTIVE

To elucidate 3-dimensional (3-D) cytomorphology in fine needle aspiration biopsy (FNAB) of subacute thyroiditis.

STUDY

DESIGN

Ultrasound-guided FNAB was performed on the inflamed area of the thyroid from 4 patients with subacute thyroiditis. The aspirates were stained and observed under a light microscope (LM). The aspirates were also fixed, dehydrated, critical point dried, spattered with gold ions and observed with a scanning electron microscope (SEM). For transmission electron microscopy (TEM), the specimen was fixed, dehydrated, embedded in an Epon mixture, cut with an ultramicrotome, mounted on copper grids, electron doubly stained with uranium acetate and lead citrate, and observed with TEM. Findings with SEM were correlated with those with LM and TEM.

RESULTS

Under SEM, 3-D cytomorphology of subacute thyroiditis displayed loss of a uniform, honeycomb cellular arrangement; variation in size; and decrease or shortening of microvilli in follicular cells, which corresponded to varying degrees of cellular degeneration under TEM. Giant cells that were round or ovoid were also noted with SEM.

CONCLUSION

Loss of a uniform, honeycomb cellular arrangement; variation in size and decrease or shortening of microvilli in follicular cells; and appearance of round or ovoid giant cells were characteristic 3-D cytomorphology findings in FNAB of subacute thyroiditis.