Hyalinizing trabecular tumor of the thyroid gland.

Hyalinizing trabecular tumor was first described by Carney et al. (1) in 1987 and is a rare benign tumor of the thyroid gland that shares some of the microscopic features of medullary and papillary thyroid carcinoma. Hyalinizing trabecular tumor derives from follicular cells, and it is characterized by an apparent trabecular pattern and intratrabecular hyalinization. In this study, we present the case of a 40-year-old female patient with thyroid gland nodules, whose ultrasound results, clinical behavior, and fine-needle aspiration biopsy results were suspicious; the pathology after thyroidectomy indicated hyalinizing trabecular tumor. We aimed to show the role of clinical behavior, radiology, fine-needle aspiration, and histological and immunohistochemical analysis in the differential diagnosis of hyalinizing trabecular tumor. Hyalinizing trabecular tumor which can be confused with papillary and medullar carcinoma of the thyroid gland, is mostly benign but some malignant and metastatic cases have been reported. Therefore, diagnosis, treatment, and follow-up steps of Hyalinizing trabecular tumor should be planned in consideration of a malignant potential.