title: Cytologic Findings of Thyroid Carcinoma Showing Thymus-like Differentiation: A Case Report.
abstract: Carcinoma showing thymus-like differentiation (CASTLE) is a rare carcinoma of the thyroid or adjacent soft tissue of the neck with a histologic resemblance to thymic epithelial tumors. Although the fine-needle aspiration (FNA) plays a central role in the initial evaluation of thyroid nodules, few reports about the cytologic findings of CASTLE have been found according to a review of literatures. We report cytologic findings of a case of CASTLE. A 34-year-old woman presented with a 2-month history of sore throat. The FNA showed that the smear was composed of three dimensional clusters and sheets. The tumor cells were round to ovoid with high nuclear : cytoplasmic ratios. The nuclei were vesicular with small nucleoli. There were some tumor cells showing keratinization. Some lymphocytes were found on the background and within clusters. The presence of poorly-differentiated tumor cells with a focal keratinization and a lymphocytic background on the FNA is suggestive of CASTLE.
authors.affiliation: Department of Pathology, Inje University Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea.
authors.forename: Sunhee
authors.initials: S
authors.lastname: Chang
authors.forename: Mee
authors.initials: M
authors.lastname: Joo
authors.forename: Hanseong
authors.initials: H
authors.lastname: Kim
keywords: Biopsy, fine-needle; Cytodiagnosis; Thymoma; Thymus gland; Thyroid gland