Macrofollicular variant of XXXX of the thyroid: a histologic, cytologic, and immunohistochemical study of 3 cases and review of the literature.

@entity8170 @entity1377 @entity5 @entity2225 @entity189 @entity876 @entity3 @entity652 @entity7457
CONTEXT: The macrofollicular variant of @entity1377 of the thyroid is a rare entity described by J. Albores-Saavedra and colleagues in 1991. It is characterized histologically by a predominance of macrofollicles and clinically by a low incidence of @entity3 . This entity may represent a source of diagnostic error, since it can be easily misinterpreted as a macrofollicular @entity652 or @entity8170 . DESIGN: In this study, we describe 3 cases of @entity1377 of the thyroid with a macrofollicular growth pattern and review the literature. RESULTS: The fine-needle aspiration biopsies in 2 cases showed large cells with optically clear nuclei and nuclear grooves, suggestive of @entity1377 of the thyroid. In one case, the cytology showed no signs of @entity5 . In all cases, the @entity5 showed a combination of the conventional follicular variant of @entity1377 of the thyroid and macrofollicles (diameter, >250 microm) occupying more than 50% of the cross-sectional area. Cytologic features were large, cuboidal cells with optically clear, ground-glass nuclei with smooth outlines, a fine chromatin pattern, nuclear grooves, and pseudoinclusions. The colloid was dense and more eosinophilic than in adjacent normal follicles. In 2 cases, there was capsular or blood vessel infiltration, and one @entity5 had metastasized to a cervical lymph node. One @entity5 recurred 1 year later as an @entity189 . Immunohistochemical staining showed a positivity of the @entity5 cells for cytokeratins 7, 17, and 19, @entity7457 , and galectin-3 and a negativity for @entity2225 and @entity876 . CONCLUSIONS: Although it has been suggested that this @entity5 is a highly differentiated variant with a favorable prognosis, our study shows that its biologic behavior is not conclusive because metastases and recurrences with dedifferentiation may occur.
