Large needle biopsy diagnosis of thyroid carcinoma: problem areas.

The major problem area in the diagnosis of thyroid cancer by large needle biopsy is in the identification of follicular carcinoma and the follicular variant of papillary carcinoma. Diagnosis of these tumors is facilitated by use of Bouin's solution as an initial fixative to duplicate the nuclear detail seen in the surgical specimen. As specimen size precludes demonstration of invasive characteristics, details of cellular and follicular architecture must be relied upon to indicate the need for surgical biopsy.