갑상선 세침흡인세포검사에서 소포병변 및 소포종양 진단의 딜레마 (Diagnostic Dilemma of a Follicular Lesions/Neoplasm in Thyroid Fine Needle Aspiration Cytology)

서지정보

· 발행기관 : 대한갑상선학회
· 수록지 정보 : International Journal of Thyroidology / 5권 / 2호 / 104 ~ 108페이지
· 저자명 : 정찬권

초록

Fine needle aspiration cytology (FNAC) of thyroid nodules is the best screening test for the selection of patients that may require surgical management. However, the diagnosis of follicular neoplasm on FNAC remains a gray area and the main differential diagnosis of follicular neoplasm includes benign (nodular hyperplasia and follicular adenoma) and malignant (follicular carcinoma and follicular variant of papillary carcinoma) lesions.
The cytologic diagnosis of follicular neoplasm is based on the high cellularity, microfollicular or trabecular pattern, overlapping follicular cells, and scanty or absent colloid. Histologically, the diagnosis of follicular carcinoma requires the presence of tumor capsular invasion or vascular invasion. In the follicular variant of papillary carcinoma, nuclear features of papillary carcinoma may be subtle and seen in only a small number of cells, and thus may not be readily appreciated. Analyses of BRAF and RAS point mutations and RET/PTC and PAX8/PPARγ rearrangements have been reported to be a useful ancillary tool for diagnosing thyroid cancer in cytology specimens. The presence of BRAF or RET/PTC mutation is a strong indicator of papillary carcinoma. PAX8/PPARγ rearrangement is exclusively found in follicular carcinoma. RAS mutations are found in follicular adenoma/carcinoma and follicular variant of papillary carcinoma. Therefore, molecular testing of FNAC samples can improve the accuracy of cytologic diagnosis.

영어초록

Fine needle aspiration cytology (FNAC) of thyroid nodules is the best screening test for the selection of patients that may require surgical management. However, the diagnosis of follicular neoplasm on FNAC remains a gray area and the main differential diagnosis of follicular neoplasm includes benign (nodular hyperplasia and follicular adenoma) and malignant (follicular carcinoma and follicular variant of papillary carcinoma) lesions.
The cytologic diagnosis of follicular neoplasm is based on the high cellularity, microfollicular or trabecular pattern, overlapping follicular cells, and scanty or absent colloid. Histologically, the diagnosis of follicular carcinoma requires the presence of tumor capsular invasion or vascular invasion. In the follicular variant of papillary carcinoma, nuclear features of papillary carcinoma may be subtle and seen in only a small number of cells, and thus may not be readily appreciated. Analyses of BRAF and RAS point mutations and RET/PTC and PAX8/PPARγ rearrangements have been reported to be a useful ancillary tool for diagnosing thyroid cancer in cytology specimens. The presence of BRAF or RET/PTC mutation is a strong indicator of papillary carcinoma. PAX8/PPARγ rearrangement is exclusively found in follicular carcinoma. RAS mutations are found in follicular adenoma/carcinoma and follicular variant of papillary carcinoma. Therefore, molecular testing of FNAC samples can improve the accuracy of cytologic diagnosis.

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