Minute Hyalinizing Trabecular Tumor Misinterpreted as a Blood Vessel on Ultrasonography: A Case Report

Introduction

Hyalinizing trabecular tumor (HTT) of the thyroid is a rare tumor of follicular cell origin with a trabecular growth pattern and marked intratrabecular hyalinization [Carney JA, et al. Am J Surg Pathol 2008; 32: 1877–1889]. On fine needle aspiration cytology (FNAC), it is often interpreted as papillary thyroid carcinoma (PTC) because of the presence of intranuclear cytoplasmic inclusions [Kuma S, et al. Acta Cytol 2003; 47: 399–404]. Few reports have described ultrasound findings of HTT [Kobayashi K, et al. J Med Ultrasonics 2007; 34: 43–47; Choi WJ, et al. Acta Radiol 2015; 56: 1113–1118; Lee S, et al. Thyroid 2011; 21: 253–259]. Reportedly, the findings were similar to follicular adenoma. Recently, we encountered a case of minute HTT that was incidentally observed by ultrasonography and interpreted as a blood vessel. To the best of our knowledge, our case is the smallest HTT detected by ultrasound examination. We describe herein the ultrasound findings of a minute HTT that we experienced and discuss the significance of detecting such a lesion.