CD44 IMMUNOSTAINING OF THYROID FINE-NEEDLE ASPIRATES DIFFERENTIATES THYROID PAPILLARY CARCINOMA FROM OTHER LESIONS WITH NUCLEAR GROOVES ANDINCLUSIONS

BACKGROUND, Although nuclear grooves and inclusions are considered to be characteristic cytologic features of thyroid papillary carcinoma, a variety of other thyroid lesions may on occasion display these featur es in fine-needle aspiration specimens. METHODS. The authors evaluated the immunocytochemical staining of 16 fine-needle aspirations of thyr oid papillary carcinoma and 14 aspirations of thyroid lesions confirme d to be other than papillary carcinoma but that included cells with nu clear grooving and/or inclusions, comprised of multinodular goiter (fo ur cases), follicular adenoma (two cases), Hurthle cell adenoma (two c ases), pure thyroiditis (three cases), and thyroiditis with nodular hy perplasia (three cases). CD44 previously has been shown to be selectiv ely expressed in thyroid papillary carcinoma. RESULTS, Of 16 surgicall y confirmed cases of thyroid papillary carcinoma featuring nuclear gro oves and inclusions on fine-needle aspiration, 14 (88%) stained intens ely for CD44 in a membranous pattern. Of the 14 nonpapillary thyroid c arcinoma cases, only 1 (7%), a Hurthle cell adenoma, featured membrano us CD44 staining. The difference in the proportion of cases with CD44 staining between the two groups was statistically significant (chi-squ are test, P < 0.001). CONCLUSIONS, The authors conclude that immunosta ining for CD44 can readily be performed on thyroid fine-needle aspirat ion specimens and that, for specimens featuring nuclear grooves and in clusions, the presence or absence of staining for CD44 may be of value in the distinction between thyroid papillary carcinoma and other lesi ons that may share some of the cytologic features of papillary carcino ma. (C) 1997 American Cancer Society.