Hyalinizing Trabecular Tumor Research Articles

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

Hyalinizing trabecular tumor (HTT) is a rare thyroid tumor with low to minimal malignant potential. HTT is often misinterpreted as other thyroid tumors, including papillary thyroid carcinoma (PTC) and medullary thyroid carcinoma (MTC), on fine-needle aspiration (FNA) cytology, because of its overlapping cytologic features, such as nuclear grooves and intranulcear pseudoinclusions. Although cytopathologists cannot definitely conclude HTT by FNA cytology, suspicion of HTT is necessary to avoid misdiagnosing HTT as PTC or MTC and to avoid unnecessary aggressive treatment. Here, we report a case of HTT with novel cytologic features in CellPrep liquid based cytology that was diagnosed as suspicious for papillary carcinoma by FNA and finally diagnosed as HTT in the surgical specimen.

A Case of Thyroid Hyalinizing Trabecular Tumor Mistaken for Papillary Carcinoma in Aspiration Cytology

Hyalinizing trabecular tumor (HTT) of the thyroid gland is a rare neoplasm and only less than 100 cases have been reported so far. It is characterized by hyalinizing stroma with trabecular growth pattern and has an indolent clinical course. Because of its histologic features, it is frequently misdiagnosed as papillary or medullary carcinoma in fine needle aspiration cytologic findings. The tumor is benign or low malignant potential and thyroid lobectomy is recommended for adequate treatment. We recently experienced a case of thyroidal HTT in a 57-year-old man, who presented with a right thyroid nodule that was suspicious of papillary carcinoma in aspiration cytology. We report the unique and rare disease entity with brief literature review.

Stromal tiny black dots, like "sugar-coated", of von Kossa stain is a diagnostic clue to hyalinizing trabecular tumor of the thyroid gland.

Hyalinizing trabecular tumor (HTT) is a rare low-grade tumor, and a prominent feature is the basement membranous stroma. We assume that such characteristic stromal findings of HTT are related to calcium deposition, and examined HTT samples by von Kossa special staining. There has been no report describing von Kossa special staining for such stroma. We collected 12 cases of HTT and 30 cases of papillary thyroid carcinoma (PTC) that had matched age, gender, tumor size, and surgical procedure characteristics as a control group. We compared the staining pattern and degree of von Kossa positivity between HTT and PTC, and a grading system of von Kossa stain was adopted to highlight differences between them. On von Kossa staining, all HTT revealed many tiny black dots around vessels in the hyalinized stroma, like "sugar-coated", and a high degree of calcium deposition in most cases, whereas PTC showed sparse stromal calcification in some cases. The degree of von Kossa staining was significantly different between the two groups. This is the first report describing abundant tiny black dots, like a "sugar-coated" appearance, of von Kossa stain in HTT. Here, we propose this finding can be a useful diagnostic clue to HTT.

False-positive cytopathology results for papillary thyroid carcinoma: A trap for thyroid surgeons.

Current preoperative diagnosis of thyroid nodules remains imperfect despite recent advances in cytopathology and molecular diagnostics. False positivity in preoperative fine-needle aspiration cytology (FNAC) may lead to overtreatment of patients, including total thyroidectomy, and sometimes to lawsuits for misdiagnosis and malpractice. In this study, we analysed clinical characteristics and pathologic findings in patients with false positivity for papillary thyroid carcinoma (PTC) in FNAC. We retrospectively reviewed permanent pathology results from 3788 patients who underwent thyroid surgery. Among them, 48 patients had lesions that were deemed suspicious or positive (Bethesda class V or VI) for PTC in preoperative FNAC. We reviewed clinic-pathologic data, radiologic findings and surgical planning in these patients. The prevalence of pathologic thyroiditis was significantly higher among patients with false-positive FNAC results than in those with confirmed PTC (54.2% vs 9.2%, P<.001). The analysis of the permanent pathology reports showed that 26 patients had chronic lymphocytic thyroiditis and 22 patients had no evidence of thyroiditis. Among the patients without pathologic thyroiditis, 19 patients (86.4%) had nodular hyperplasia and three (13.6%) had follicular adenoma, while among the patients with pathologic thyroiditis, seven (26.9%) had no nodule, 14 (53.8%) had nodular hyperplasia, two (7.7%) had hyalinized nodules, two (7.7%) had follicular adenoma and one (3.8%) had a hyalinizing trabecular tumour. In 42 patients, the extent of surgery (total thyroidectomy or hemithyroidectomy) was to be determined according to the intra-operative frozen section biopsy results. Among them, four (10.5%) had inconclusive frozen section results, and 38 (90.5%) had benign results on frozen section. Patient counselling about the possibility of false positivity is still important. And the presence of thyroiditis might create confusion in the interpretation of cytopathologic results.

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.

Pitfalls in fine needle aspiration cytology diagnosis of hyalinizing trabecular tumour

Hyalinizing Trabecular Tumour (HTT) is rare among follicular cell neoplasm and contributes less than 1% of all primary thyroid gland tumours. It is commonly seen in middle age with female prepondenrance. HTT is a benign to malignant potential tumour. The tumour has definite histomorphological features. However cytological diagnosis is challenging. The definite cytological diagnosis of HTT is important to plan the surgical treatment. Here we present two case reports; one in 72 years male and other in 22 years female highlighting the pitfalls in the cytological diagnosis of HTT.

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

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.

The ultrasonography features of hyalinizing trabecular tumor of the thyroid gland and the role of fine needle aspiration cytology and core needle biopsy in its diagnosis.

Hyalinizing trabecular tumor (HTT) of the thyroid gland is a rare, benign neoplasm of follicular cell origin. Misdiagnosis of HTT as either papillary or medullary thyroid carcinoma after fine-needle aspiration (FNA) may lead to unnecessary surgery. To evaluate the ultrasonography (US) findings of HTT of the thyroid gland and the role of FNA cytology and core needle biopsy (CNB) in its diagnosis. Data from 24 patients with a histopathological diagnosis of HTT between January 2000 and May 2013 were retrospectively analyzed. US findings were categorized according to shape, margin, orientation, echogenicity, composition, calcification, and vascularity. Cytologic and histologic results of FNA, CNB, and surgery were reviewed. US revealed the following tumor features: oval-to-round (24/24), solid (22/24), smooth margin (21/24), hypoechoic or marked hypoechogenicity (18/24), and peri- and/or intranodular vascularity (17/17). Malignant US features such as marked hypoechogenicity (n = 7) and a spiculated margin (n = 3) were also observed. Final confirmation was by surgery in 22 patients and by CNB in two patients. All 19 patients who underwent FNA were initially misdiagnosed, including 12 with malignancies and five with atypia of undetermined significance. All four patients who underwent CNB were correctly diagnosed with HTT. The histology of CNB specimens suggested HTT, which was confirmed by immunostaining of MIB-1. HTT should be suspected when the cytological diagnosis of papillary thyroid carcinoma is made after FNA without malignant US findings. CNB could prevent unnecessary surgery for HTT.

Hyalinizing Trabecular Tumor of the Thyroid Gland

A 34-year-old woman with a 4-year history of a slowly enlarging thyroid gland underwent a total thyroidectomy. Histologic sections showed multinodular colloid goiter. In addition, a 1.2 centimeter diameter discrete mass with a solid white cut surface was noted within the left lobe.&#x0D; Sections from the left lobe mass show a well-demarcated tumor whose cells are arranged in trabecular and nested growth patterns. (Figure 1) The cells are polygonal to spindly and have ample eosinophilic, slightly granular cytoplasm and oval to angular nuclei that are often grooved. (Figure 2) Hyaline material and a delicate fibrovascular stroma surround the nests and trabeculae, and occasional psammoma bodies are seen. (Figure 3) These features led us to a diagnosis of hyalinizing trabecular tumor.&#x0D; Hyalinizing trabecular tumor (HTT) is a rare thyroid neoplasm of follicular cell derivation.1, 2 The tumor occurs in adults with a wide age range (4th – 7th decades) and a mean age of 47 years. It is more common in females.1 The classic histologic findings are of a solid circumscribed epithelial neoplasm with or without a thin capsule composed of medium to large-sized polygonal to fusiform cells that are arranged in alveolar, trabecular and nested groups. The cells have finely granular, acidophilic, amphophilic or clear cytoplasm. Nuclei often have prominent grooves and small nucleoli. Calcospherites (psammoma bodies) may be present. Colloid is scant or absent. 1, 2, 3&#x0D; &#x0D; Because of overlapping nuclear features, a follicular variant of papillary thyroid carcinoma is a differential diagnosis. Histologic features are usually sufficient to distinguish the entities as a nested-alveolar architecture is rarely a prominent feature of a papillary carcinoma.2 Immunohistochemistry may be of aid in this distinction especially in difficult cases with limited material. Cytokeratin 19 and HBME1 are negative in HTT and are usually positive in papillary thyroid carcinomas.4, 5, 6 Neuroendocrine markers are also negative in HTT and are positive in medullary thyroid carcinomas and paragangliomas.2&#x0D; &#x0D; HTT is of uncertain malignant potential, and a 2008 review of 119 HTTs has shown only one case progressing to malignancy.3 The majority of cases have behaved in a benign fashion and thus may be treated conservatively.1

Hyaline matrix in hyalinizing trabecular tumor

Hyalinizing trabecular tumor (HTT) is a rare neoplasm which usually follows an indolent clinical course. The cytologic diagnosis of HTT can be challenging as these neoplasms share cytomorphological features with other thyroid neoplasms and paraganglioma. In fine-needle aspiration (FNA) smears a diagnosis of papillary thyroid carcinoma (PTC) or suspicion of PTC is often made. Herein we report cytologic findings in two patients with HTT examined by FNA. The key to a correct diagnosis is the recognition of a hyaline and colloid/amyloid-like material in the background of the smears. Immunocytochemical examination showing aberrant membranous and peripheral cytoplasmic staining for MIB-1 can help in rendering a correct diagnosis.

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

BackgroundFine-needle aspiration cytology (FNAC) is very accurate in detecting papillary thyroid carcinomas (PTCs). According to the Bethesda system for reporting thyroid cytopathology, the risk for malignancy is 97–99% when FNAC is used to diagnose PTC; the malignancy risk is 60–75% when FNAC results in suspected PTCs. The presence of hyalinizing trabecular tumor (HTT) of the thyroid can cause misdiagnosis because its cytological features mimic PTCs. However, the use of frozen section analysis can assist in the recognition of unique architecture features of HTT, and thus may help prevent the undertaking of an unnecessarily aggressive operation. MethodsWe retrospectively reviewed all patients diagnosed with HTT by permanent histopathology from February 2009 to October 2013. After acquired agreement of the patients, we analyzed all data and reviewed another nine cases of HTT reported in the English-language medical literature to examine the efficacy of frozen section. ResultsThere were six patients included in our research (5 women and 1 man), with an average age of 48.8 years. Using frozen section, four patients were diagnosed with HTT and two patients were misinterpreted as PTC. Consequently, four patients had lobectomy and two patients had total thyroidectomy, with no surgical complications. Of the nine cases of HTT reviewed from the English literature, the use of frozen section showed three HTT cases, three PTC cases, two medullary thyroid carcinoma cases, and one deferral case. Overall, the use of frozen section as a diagnostic method prevented additional surgical resection in eight patients (53%). ConclusionFrozen 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 gland: A puzzling entity on fine needle aspiration cytology

Hyalinizing trabecular tumor (HTT) is a rare unique but controversial thyroid neoplasm, characterized by prominent trabecular growth pattern and stromal hyalinization. Whether HTT is a benign tumor or a variant of papillary thyroid carcinoma (PTC) is still unclear. Cytology findings of HTT have been described in few reports. Cytological features of HTT frequently overlap with those of PTC and medullary thyroid carcinoma, which can lead to frequent misdiagnosis. In order to avoid overtreatment like total thyroidectomy, pathologist should be aware of cytological features of HTT. We present a case of 35-year-old female with a right-side thyroid swelling for three years. Fine needle aspiration cytology was performed. According to The Bethesda System for Reporting Thyroid Cytopathology, cytological diagnosis of benign thyroid neoplasm was made. Histopathology of the right thyroidectomy specimen showed HTT. Accurate preoperative diagnosis of HTT requires a very meticulous and cautious approach in the evaluation of cytological features. Trabecular pattern of cells, vague curved nuclear palisading, radiating arrangement of cells around hyaline material, spindled to elongated cells, filamentous cytoplasmic processes with ill-defined cell border and yellow bodies are important diagnostic features of HTT. Nuclear features alone are insufficient for the diagnosis of HTT. Any suspicious cytology of thyroid lesion should follow hemithyroidectomy and histopathological evaluation.

Hyalinizing Trabecular Tumor (HTT) of Thyroid: Two Case Report

Hyalinizing Trabecular Tumor (HTT) of Thyroid: Two Case Report

HBME‐1 expression in hyalinizing trabecular tumours of the thyroid gland

Hyalinizing trabecular tumour (HTT) is a rare thyroid neoplasm with a trabecular growth pattern, marked intratrabecular hyalinization and nuclear features of papillary thyroid carcinoma (PTC). Immunohistochemical HBME-1 expression was reported recently in PTC, but not in HTT. To clarify further the value of HBME-1 expression as a tool in differential diagnosis, we investigated the immunophenotype of HTT. Eight HTT diagnosed from 1997 to 2012 were reviewed on H&E-stained tissue sections and analysed for HBME-1, galectin-3, CK19 and Ki67 expression by immunohistochemistry. Three of eight HTTs (37.5%) were HBME-1 positive, with staining of tumour cells as well as of intratrabecular hyaline matrix material. All cases were CK19 negative. Galectin-3 was expressed weakly in four of eight cases (50%). Five of eight cases (62.5%) showed weak-to-moderate cytoplasmic Ki67 positivity. Immunohistochemical HBME-1 expression is present in HTT and may not serve as a reliable marker in differentiating HTT from PTC. The HBME-1 positivity of the hyaline matrix suggests that this material is partly of cytoplasmic origin.

Hyalinizing trabecular tumor of the thyroid: Case report and review of the literature

In 1987, Carney et al described a rare thyroid tumor termed hyalinizing trabecular adenoma presenting characteristics consisting of a trabecular growth pattern and hyalinizing stroma. In subsequent reports, the observed nuclear features and RET alterations led this tumor to be linked to papillary carcinoma. Subsequent reports concerning hyalinizing trabecular carcinoma further complicated its classification. To avoid uncertainties, the definition of hyalinizing trabecular tumor (HTT) is more widely used. Herein, a case of HTT is reported in detail, and the circumstances are also discussed. HTT is thought to be particularly differentiated from papillary carcinoma despite the identical high frequency of nuclear grooves and cytoplasmic inclusions, and MIB-1-positive staining is one of the most accurate diagnostic methods due to the distinct membrane-positive pattern noted in HTT. It is believed that most HTTs are benign and lobectomy is the standard treatment. Pathologists should offer surgeons information concerning diagnosis overlapping with effective treatment.

Difficultés diagnostiques en cytopathologie thyroïdienne : à propos de deux cas de tumeur trabéculaire hyalinisante

Hyalinizing trabecular tumors (HTT) are very rare thyroid tumors whose diagnosis is difficult, particularly in cytology. They are frequently diagnosed as papillary carcinomas due to the cytological similarities between those two tumors (anisocariosis, intranuclear cytoplasmic inclusions, nuclear grooves and nuclear overlapping). Here, we report two HTT cases which were initially diagnosed as papillary carcinoma, on the preoperative cytology and for which the patients underwent total thyroidectomy with lymph node dissection. From these two cases and a literature review, we have searched for diagnostic criteria which could increase the sensitivity of HTT diagnosis in thin layer cytology. We have found that only the identification of the fibrillar and hyaline material within the cellular cluster of the HTT seems discriminating between both tumors, even though it is difficult to diagnose it is difficult to diagnose on thin layer cytology. One major help for the diagnosis would be the typical membranous and cytoplasmic MIB-1 immunostaining. However, no experiment has been undertaken with thin layer smears for HTT.

Immunohistochemical subclassification of thyroid tumors with a prominent hyalinizing trabecular pattern

The purpose of this study was to evaluate the immunohistochemical characteristics of thyroid tumors with a prominent hyalinizing trabecular pattern (TTHTP). Immunohistochemical stains for thyroid transcription factor 1 (TTF-1), thyroglobulin, CD56, cytokeratin (CK) 19, galectin-3, and Ki-67 were performed on 16 cases of TTHTP. All TTHTPs were positive for TTF-1 and thyroglobulin, and nine cases expressed CD56 and Ki-67. Of these nine cases, seven satisfied the strict criteria of Carney, and four cases were positive for CK19 or/and galectin-3 and negative for Ki-67 and CD56. The remaining three cases had no Ki-67, CD56, CK19 or galectin-3 expression. All TTHTPs meeting the criteria of Carney were hyalinizing trabecular tumors (HTT), and TTHTPs which did not satisfy the criteria of Carney were subclassified according to the immunohistochemical results as the HTT type [Ki-67 (+) and CD56 (+)], papillary thyroid carcinoma (PTC) type [CK19 or galectin-3 (+)/Ki-67 (-) and CD56 (-)], or null type [Ki-67 (-), CD56 (-), CK19 (-) and galectin-3 (-)]. TTHTPs with typical histologic features and/or with typical immunohistochemical manifestations can be categorized as HTT, and the remaining TTHTPs should be categorized as the PTC or null type.

The Ultrasonography Features of Hyalinizing Trabecular Tumor of the Thyroid Are More Consistent with Its Benign Behavior than Cytology or Frozen Section Readings

Hyalinizing trabecular tumors of the thyroid (HTT) is a rare entity. Most behave as benign neoplasms, but their cytological features are challenging and can be similar to those of papillary thyroid carcinoma (PTC). The aim of this study was to compare the ultrasonography (US) readings of HTT with the cytology and frozen section readings. We retrospectively analyzed the US and cytology features in 10 patients (mean age, 47.5 years, range 26-81; M:F, 1:9) seen between March 2006 and November 2009 who had a histopathological diagnosis of HTT. The US findings were categorized according to the size, shape, margin, echogenicity, echotexture, presence of hypoechoic halo, and microcalcifications. Preoperative fine-needle aspiration cytology, frozen section results, and surgical treatment were reviewed. US features of HTT were compared with those of other tumors including follicular adenomas, follicular variant of PTCs, and conventional PTC. Out of the 10 patients in our series, 7 underwent total thyroidectomy, and 3 had lobectomy. The sizes of the HTTs ranged from 0.6 to 4.2 cm (mean, 1.77 cm). The most common US features were solid texture (10/10), oval to round shape (10/10), a well-defined aspect (10/10), hypoechoic character (8/10), heterogeneous character (7/10), the presence of a hypoechoic halo (8/10), and no microcalcifications (10/10). The US diagnosis was indeterminate in all but one case and that was read as a benign lesion. As far as the shape and margin US features were concerned, HTT was considered to be most similar to follicular adenomas and follicular variant of PTC, but not to classical PTC. The cytology reading was PTC in 6 of 10 cases, suspicious for PTC in 2, and a HTT versus PTC in 2. The histological diagnosis of frozen sections, when performed, was PTC in three, HTT in three, medullary thyroid carcinoma in two, and deferred in one. HTT often appears similar to follicular neoplasm on US, but it can be misjudged on cytology as PTC, even in frozen sections. HTT should be included in the list of discordant US-cytology readings of thyroid tumors. This rare tumor might be suspected more often preoperatively by careful attention to cytology in the context of the US reading.

Gialiniziruyushchaya trabekulyarnaya opukhol' shchitovidnoy zhelezy

The paper describes a case of thyroid hyalinizing trabecular tumor in a 55-year-old woman. Cytological examination of her fine-needle biopsy specimen showed separately lying tumor cells with intracellular cytoplasmic inclusions. Its cytological study determined the trabeculoalveolar structures formed by tumor cells, the intercellular space exhibited a homogenous eosinophilic matter that yielded a positive Schick's test, laminated calcinates that mimick psammoma bodies. Immunophenotyping of the neoplasm revealed a positive reaction with antibodies to thyroglobulin, a negative reaction to galectin-3 and cytokeratin-19, and membrane Ki-67 expression, which suggests the low malignancy potential.

Hyalinizing trabecular tumor of the thyroid gland

Hyalinizing trabecular tumor (HTT) is an unusual and controversial lesion of the thyroid gland. Some have considered it a unique entity, some have considered it a variant of papillary carcinoma, and still others have considered it a nonspecific pattern that may be seen with a variety of thyroid lesions. The histological and ultrastructural characteristics of this thyroid neoplasm are well documented; however, its cytological diagnosis by fine needle aspiration cytology (FNAC) remains challenging. The cytomorphological features of this entity overlap with both papillary and medullary carcinoma to a varying extent. We report a case of HTT with cytological evaluation by FNAC in a 28-year-old male.