Post-fine-needle Aspiration Cytology Changes of Thyroid Gland

Overview

Due to the introduction of fine needle aspiration cytology (FNAC) to the routine clinical preoperative egamination surgical pathologists are faced with thyroid gland specimens with FNAC-induced secondary changes. These changes can cause diagnostic difficulties and be a Bource of incorrect diagnosis. Authors present a review of FNAC-induced changes with differential diagnostic criteria helpful in these pitfalls. FNAC-induced changes can be schematically divided finto two major groups - recent ones (intranodal bleeding and/or necrosis) and subacute/late ones (proliferation of granulation tissue with predominance of myofibroblasts or endothelial cells, resorptive pseudogantomathous granulomas, formation of sarcoid-like granulomas, capsular pseudoinvasion and scarring).Pathologists should be informed about the previously performed FNAC and must be aware of these lesions to prevent their misinterpretation.

Key words:
thyroid gland - fine needle aspiration cytology - postaspiration changes - necrosis - myofibroblast - sarcoid-like granuloma