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

Abstract

Purpose:The goal of this study was to evaluate the clinicopathological and imaging features of thyroid nodules surgically diagnosed as hyaline trabecular tumor (HTT), and to assess the role of cytology and frozen sections (FS) in the diagnosis of HTT.Methods:This study included 21 thyroid nodules in 21 patients treated from August 2005 to March 2015 (mean age, 53.3 years) who were either diagnosed as HTT or had HTT suggested as a possible diagnosis based on cytology, FS, or the final pathology report. Patients’ medical records were retrospectively reviewed for cytopathologic results and outcomes during the course of follow-up. Sonograms were reviewed and categorized.Results:Twelve nodules from 12 patients were surgically confirmed as HTT. Ultrasonography (US)-guided fine needle aspiration (FNA) was performed on 11 nodules, of which six (54.5%) were papillary thyroid carcinoma (PTC) or suspicious for PTC and three (27.3%) were HTT or suspicious for HTT. Intraoperative FS suggested the possibility of HTT in seven nodules, of which four (57.1%) were confirmed as HTT. US-FNA suggested the diagnosis of HTT in 10 nodules, of which three (30.0%) were confirmed as HTT. Common US features of the 12 pathologically confirmed cases of HTT were hypoechogenicity or marked hypoechogenicity (83.4%), absence of calcifications (91.7%), parallel shape (100.0%), presence of vascularity (75.0%), and probable benignity (58.3%).Conclusion:HTT should be included in the differential diagnosis of solid tumors with hypoechogenicity or marked hypoechogenicity and otherwise benign US features that have been diagnosed as PTC through cytology.

Core Needle Biopsy of the Thyroid: 2016 Consensus Statement and Recommendations from Korean Society of Thyroid Radiology

“…Hyalinizing trabecular tumors pose a challenge to diagnosis due to frequent cytological diagnosis of papillary thyroid carcinoma after FNA (919293). Several studies suggested a role for CNB in this rare thyroid tumor (9194).…”

Hyalinizing trabecular tumour of the thyroid: fine-needle aspiration cytological diagnosis and correlation with histology

“…In two out of three small published series investigating ultrasonographical features of HTT, the authors found that none of the patients showed any findings indicative of malignancy;13 14 in the third one, only 29% of patients showed malignant ultrasound (US) findings 15. Overall, authors described the vast majority of HTT as being solid tumours, hypoechogenic or markedly hypoechogenic 13–15…”

Pitfalls in fine needle aspiration cytology diagnosis of hyalinizing trabecular tumour

“…Later it was described in detail about the trabecular growth pattern and marked intratrabecular hyalinizing stroma in 1987 by Carney (Casey et al, 2004;Gupta et al, 2010;Howard et al, 2013;Jang et al, 2016;Li et al, 2012;McCarthy et al;Ninan et al, 2011;Santosh et al, 2011). Various etiological factors are put forth as; radiation exposure, arising in a background of chronic lymphocytic thyroiditis and multinodular goitre (MNG).…”

“…However the hyaline material in HTT is solid/homogenous and well defined than amyloid and not contain the streaked nuclear material as in amyloid. Cells in HTT do not have cytoplasmic granules (Gupta et al, 2010;Howard et al, 2013;Jang et al, 2016;McCarthy et al). In the present case reports, in the first case the cells showed cytoplasmic features as mentioned above, however the nuclear features were absent and hence the cells were considered as Hurthle cells.…”

“…However this shows the poor cyto-histo correlation in the present cases considering cytological diagnosis of HTT. One study has shown the poor performance of even ultrasound guided FNAC in cytological diagnosis of HTT (Jang et al, 2016).…”