Hyalinizing trabecular tumor of thyroid: Does frozen section prevent unnecessarily aggressive operation? Six new cases and a literature review

Abstract

Frozen section can sometimes but not always be used to diagnose HTT. When HTT is diagnosed by its trabecular pattern through the use of frozen section, it may prevent total thyroidectomy.

Hyalinizing trabecular tumor of the thyroid: diagnosis of a rare tumor using ultrasonography, cytology, and intraoperative frozen sections

“…Several studies have retrospectively reviewed the preoperative cytologic results of surgically proven HTT, and the presence of cytological features suggestive of HTT have been reported in 58%-100% of cases classified as PTC or suspicious for PTC [ 2 , 7 , 8 , 13 ]. In contrast, the same studies reported that the diagnosis of HTT was suggested in preoperative US-FNA in approximately 0%-20% of cases [ 2 , 7 , 8 , 13 ], which demonstrates the low accuracy of cytology in the diagnosis of HTT. The results of our study are similar to previous findings; among the eleven patients who underwent US-FNA, 54.5% (6/11) were misdiagnosed as PTC, while approximately 27% (3/11) had findings that were interpreted as HTT or possible HTT (2/11).…”

“…With the increased awareness of HTT, attempts to predict the diagnosis of HTT based on intraoperative FS have been reported. Sung et al [ 8 ] reviewed nine patients diagnosed with HTT and found that none of the patients diagnosed as HTT based on FS were ultimately diagnosed with other thyroid malignancies such as PTC, MTC, or metastatic cancer. In our study, however, the possibility of HTT was suggested in intraoperative FS results in seven thyroid nodules in seven patients, of which only four were confirmed as HTT.…”

“…The final diagnosis of the four nodules with deferred results on FS was as follows: HTT in one, follicular adenoma in one, minimally invasive follicular carcinoma in one, and poorly differentiated carcinoma in one. As Sung et al [ 8 ] suggested, intraoperative FS may play an additional role in preventing total thyroidectomy by predicting HTT, but it has its limitations, since approximately 57.1% of the thyroid nodules with intraoperative FS suggesting the possibility of HTT had a deferred diagnosis, which may only lead to confusion and the delayed treatment of malignant tumors.…”

“…Considering its benign features, efforts have been made to identify ways of differentiating this benign tumor from other thyroid malignancies, since the preoperative diagnosis can influence the extent of surgery. Several studies have evaluated the role of preoperative ultrasonography (US)-guided FNA results [ 3 - 6 ] and frozen sections (FS) [ 8 ] in predicting the diagnosis of HTT, and for the most part have found difficulties in the accurate preoperative diagnosis of HTT by cytology or FS. Moreover, since most studies have focused on preoperative US-FNA cytology or the intraoperative FS results of thyroid nodules ultimately diagnosed as HTT, little is known about the final outcome of thyroid nodules for which HTT was suggested as a possible diagnosis on cytology or FS.…”

Hyalinizing Trabecular Tumor of the Thyroid Gland, a Diagnostic Challenge in Fine-Needle Aspiration Cytology: Case Report

“…Although cytopathologists cannot directly diagnose HTT on FNA, consideration of the possibility of HTT is important to avoid misdiagnosing HTT as a malignant thyroid neoplasm such as PTC or MTC and to avoid unnecessary overtreatment for HTT, especially when intraoperative frozen section evaluation could prevent patients from undergoing overtreatment [ 14 , 15 ].…”