title: A case of malignant thymoma mimicking thyroid carcinoma: a pitfall in fine-needle aspiration.
abstract: A case of malignant thymoma presenting as an anterior neck mass is reported. The tumor extended from the thyroid gland to the superior mediastinum. It did not accumulate Tc-99m pertechnetate, but continued to accumulate Tl-201 at the late phase. A fine-needle aspiration cytology from the tumor showed tight clusters of epithelial cells with crowded ovoid nuclei. The tumor was initially diagnosed as thyroid carcinoma, clinically and cytologically. A thymoma with a dominant epithelial component has to be considered in the differential diagnosis of a suspected papillary carcinoma of the thyroid.
authors.affiliation: The Third Department of Internal Medicine, Ehime University School of Medicine, Japan.
authors.forename: Bunzo
authors.initials: B
authors.lastname: Matsuura
authors.forename: Hitoo
authors.initials: H
authors.lastname: Tokunaga
authors.forename: Teruki
authors.initials: T
authors.lastname: Miyake
authors.forename: Sachiko
authors.initials: S
authors.lastname: Utsunomiya
authors.forename: Hisaka
authors.initials: H
authors.lastname: Minami
authors.forename: Morikazu
authors.initials: M
authors.lastname: Onji
mesh_terms: D000368:Aged; D001707:Biopsy, Needle; D002291:Carcinoma, Papillary / Q000175:diagnosis*; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D013670:Sodium Pertechnetate Tc 99m; D013794:Thallium Radioisotopes; D013945:Thymoma / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D013953:Thymus Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D013964:Thyroid Neoplasms / Q000175:diagnosis*
chemical_list: D019275:Radiopharmaceuticals; D013794:Thallium Radioisotopes; D013670:Sodium Pertechnetate Tc 99m