Hyalinizing trabecular tumor is a rare benign thyroid tumor first described by Carney et al. in 1987. The tumor is characterized by an encapsulated nodule, trabecular arrangement of polygonal, oval, elongated cells, and hyalinized stroma. It is easily confused with papillary thyroid carcinoma or medullary thyroid carcinoma on surgical and cytologic specimens. A 45-year-old man presented with an incidentally detected left thyroid mass. Fine needle aspiration was performed and papillary thyroid carcinoma was suspected. However, the surgical specimen revealed a hyalinizing trabecular adenoma. We present this hyalinizing trabecular adenoma case to share our experience with physicians and specialists.
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A Case of Multifocal Hyalinizing Trabecular Tumors of the Thyroid
Gland Suhwan Jeong, Hanaro Park Journal of Clinical Otolaryngology Head and Neck
Surgery.2021; 32(3): 308. CrossRef
A Case of Hyalinizing Trabecular Tumor of the Thyroid Gland Kun Woo Kim, Sang Joon Lee, Phil-Sang Chung, Junghwan Moon Korean Journal of Otorhinolaryngology-Head and Neck Surgery.2012; 55(12): 795. CrossRef
A hyalinizing trabecular tumor (HTT) is a rare benign thyroid tumor that can present as a solitary thyroid nodule, a prominent nodule in a multinodular goiter, or as an incidental finding within a thyroidectomy specimen. The clinical importance of this entity is that it is frequently misdiagnosed as papillary carcinoma or medullary carcinoma on fine-needle aspiration cytology or histopathologic examination. The cytology of HTT is characterized by hypercellularity, nuclear grooves, nuclear pseudoinclusions, and powdery chromatin of the tumor cells, which is frequently seen in papillary carcinomas. The histologic findings of the tumor show polygonal and spindle cells arranged in a trabecular growth pattern with the presence of a variable hyalinized stroma. Calcitonin and other neuroendocrine markers can be used to differentiate HTT from medullary carcinoma. MIB-1, galectin-3, or other cytokeratin markers help to exclude papillary carcinoma. We report a patient with a thyroid tumor misdiagnosed as a medullary carcinoma on fine-needle aspiration and finally diagnosed as HTT after total thyroidectomy and immunohistochemical examination.