Giant Hyalinizing Trabecular Tumor of the Thyroid: A Case Report and Literature Review

Hyalinizing Trabecular Tumor (HTT) is an extremely rare thyroid neoplasm. Preoperative imaging diagnosis and Fine-Needle Aspiration Cytology (FNAC) are considerably challenging. We present a case of invasive HTT, describing its clinical course and imaging manifestations.

A 49-year-old woman presented with a 12cm left thyroid mass that had been incidentally detected as a 9×8mm nodule ten years previously. Following asymptomatic gradual enlargement, she developed severe dyspnea in March 2024, prompting admission. Physical examination confirmed a large, firm left thyroid mass. Ultrasound (US) was limited by the lesion's size. Dual-Phase Contrast-Enhanced CT (DP-CECT) revealed a 12cm oval mass replacing the left lobe. US-FNAC yielded suspicious for malignancy (TBSRTC Category III). She underwent left thyroid lobectomy and isthmusectomy. Pathology and immunohistochemistry confirmed HTT with focal capsular invasion. The patient recovered uneventfully during follow-up.

Elucidating the characteristic features of HTT will facilitate early diagnosis and clinical intervention, providing valuable insights for future clinical research.