Abstract
Background : We report a case of an adenomatous nodule of the thyroid gland with papillary carcinoma-like atypical cells.
Case : A 60-year-old-man was detected by ultrasonography to have a nodule in the upper part of the left lobe of the thyroid gland. Fine needle aspiration cytology showed follicular cells arranged in sheets in a background of foamy histiocytes. Both fine needle aspiration cytology and liquid-based cytology revealed that the follicular cells had nuclei of varying size and intranuclear cytoplasmic inclusions. Macroscopic examination showed that the nodule (7×5 mm) in the pole of the left lobe of the gland was covered with a fibrous capsule. Histological examination showed a well-circumscribed nodule with an irregular fibrous containing micro- and macro follicular components. Some follicular cells had irregular enlarged nuclei, with intranuclear cytoplasmic inclusions and nuclear grooves.
Conclusion : Adenomatous goiter can rarely exhibit papillary carcinoma-like atypia, including enlarged nuclei with intranuclear cytoplasmic inclusions and nuclear grooves, as in this case. Such lesions are often difficult to distinguish from papillary carcinoma. As papillary carcinoma may rarely be present in adenomatous nodules, careful cytological evaluation is necessary.
