Ayana Suzuki

Cytological characteristics of papillary thyroid carcinoma on LBC specimens, compared with conventional specimens

The cytological findings in conventional specimens (C‐S) and liquid‐based cytology specimens (LBC‐S) are not quite same. The aim of this article is to clarify the cytological findings of papillary thyroid carcinoma (PTC) characteristic of LBC‐S.

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features: a single-institutional experience in Japan

Noninvasive encapsulated follicular variant of papillary thyroid carcinoma (PTC) was reclassified as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). To date, no studies on NIFTP have been reported in Japan. This study aimed to evaluate the clinical, cytological, and pathological findings of 54 cases of NIFTP from a single center in Japan, and compare them with those in the western countries. There were no significant differences in age, sex, or tumor size between patients with NIFTP and those with invasive encapsulated follicular variant -PTC. Ultrasound investigation showed a high suspicion lesion in 6.5% of NIFTP and 44.1% of invasive encapsulated follicular variant -PTC (p<0.001). On fine needle aspiration cytology, 75.7% of NIFTP cases were reported as suspicious for malignancy or malignant. Nuclear grooves and irregular-shaped nuclei were observed in 94.6% of cases of NIFTP. Pathologically, 27.8% cases of NIFTP and 13.0% cases of invasive encapsulated follicular variant -PTC had been originally diagnosed as macrofollicular variants of PTC. There were no NIFTP cases with nodal metastasis. We concluded that NIFTP should be renounced noninvasive encapsulated follicular variant -PTC, and should be considered as a malignant tumor with exceeding indolent behavior, and lobectomy alone should be satisfactory for the diagnosis and treatment.

Diagnostic significance of PAX8 in thyroid squamous cell carcinoma

Most types of thyroid carcinomas express PAX8 transcription factor; however, whether thyroid squamous cell carcinoma (SCC) also expresses PAX8, currently remains unknown. We herein examined the immunoreactivity of PAX8 in SCC of thyroidal and extrathyroidal origin, and discussed the diagnostic significance of PAX8. We immunohistochemically examined specimens from 11 SCC, 22 papillary thyroid carcinoma (PTC), 8 anaplastic thyroid carcinoma (ATC), and 2 mucoepidermoid carcinoma (MEC) cases as well as 5 uterine cervical SCC, 5 esophageal SCC, and 5 pulmonary SCC cases. The rates of PAX8-positive SCC, PTC, ATC, and MEC were 90.9%, 90.9%, 75.0%, and 100%, respectively. Two PAX8-negative PTC cases were cribriform variants. No uterine cervical, esophageal, or pulmonary SCC specimen reacted with PAX8 antibody. Thyroid transcription factor-1 (TTF-1) was positive in 9.1% and 95.5% of SCC and PTC cases, respectively, but negative in all ATC and MEC cases. These results demonstrate that PAX8 staining is useful for distinguishing between primary thyroid SCC and invasion or metastasis from extrathyroidal SCC. We recommend using an immunohistochemical panel of antibodies to PAX8 and TTF-1 to confirm a diagnosis of primary thyroid carcinoma.

Reappraisal of “cyst fluid only” on thyroid fine-needle aspiration cytology

According to the Bethesda System for Reporting Thyroid Cytopathology (BSRTC), cyst fluid only (CFO) cases are classified in the non-diagnostic category. To date, no large study focusing on CFO has been conducted. To reassess the diagnostic significance of CFO, we compared CFO nodules with non-diagnostic nodules excluding CFO (ND-other). We reviewed the conventional thyroid smears of 715 CFO and 766 ND-other nodules. We compared the timing of and findings at re-aspiration, the histology of resected specimens, and the proportion of malignant nodules between the two groups. Re-aspiration was performed in 9.0% of CFO and 23.8% of ND-other cases. In 12.5% of CFO and 49.4% of ND-other cases, the interval between the first and second aspirations was <3 months. Despite this, there were no cases in which cytological interpretation was complicated by the first aspiration. Overall, 77 CFO nodules (10.8%) were surgically resected; 14 were malignant. In all cases in which re-aspiration cytology revealed malignancy, the initial ultrasound interpretation was a high or intermediate suspicion pattern. The proportion of malignancies subsequently diagnosed in nodules initially classified as CFO and ND-other was 2.0% and 5.6%, respectively (p<0.01). As CFO and ND-other thyroid nodules have different clinical management and malignancy rates, we would like to assert that CFO and ND-other nodules should be separated, and that the former should be considered diagnostic. In terms of clinical management, we recommend that only CFO cases with concerning features on ultrasound undergo re-aspiration.

Cytological Findings for the Diagnosis of Primary Thyroid Mucosa-Associated Lymphoid Tissue Lymphoma by Fine Needle Aspiration

Objective: We examined cytological findings for the diagnosis of primary thyroid mucosa-associated lymphoid tissue (MALT) lymphoma by fine needle aspiration. Study Design: During the study period of 4 years, a total of 101 cases including 51 MALT lymphomas, 20 Hashimotos thyroiditis (HT), and 30 diffuse large-cell B-cell lymphomas were cytologically examined. MALT lymphomas were divided into 44 common MALT and 7 MALT lymphomas with extreme plasmacytic differentiation (MALT-EPCD). Results: (1) Small- to medium-sized cells displaying irregularly shaped nuclei with prominent nucleoli (ISN-PN) were neoplastic cells. (2) In the case of a frequency of plasma cells (PC) below 15%, the accuracy rate for distinguishing common MALT from HT was 97% for ISN-PN cell frequencies above 20% in combination with the presence of lymphoepithelial lesion clusters (LELC) and mountain range-like clusters (MRLC). The frequency of large-sized cells was below 15% in common MALT. (3) In the case of a frequency of PC above 15%, cases with a sum of PC and ISN-PN cells above 30% were MALT-EPCD. (4) MRLC were cell clusters derived from regions of follicular colonization, and LELC were cell clusters from lymphoepithelial lesions of MALT lymphomas. Conclusion: Useful cytological criteria for the diagnosis of thyroid primary MALT lymphoma, such as neoplastic cells and cell clusters, were defined.

Diagnostic value of GATA-3 in cytological identification of parathyroid tissues

Parathyroid and thyroid lesions appear morphologically similar in cytological smears, and their differentiation can be difficult. The purpose of this study was to determine the diagnostic value of T-cell-specific transcription factor GATA-3 as a marker of parathyroid differentiation in cytology specimens, and to examine the utility of liquid-based cytology (LBC). Cytology smears obtained from surgically removed parathyroid and thyroid specimens, including 15 normal parathyroid glands, 12 cases of parathyroid hyperplasia, 55 parathyroid adenomas, 2 follicular thyroid adenomas, and 3 papillary thyroid carcinomas, were examined by immunocytochemistry using antibodies against GATA-3, parathyroid hormone (PTH), chromogranin A, and thyroid transcription factor 1 (TTF-1). All normal and hyperplastic parathyroids and 98.2% of parathyroid adenomas were positive for GATA-3, while 33.3%, 66.7%, and 60.0% of them, respectively, were positive for PTH. The positive rates for chromogranin A among normal parathyroids (80.0%) and parathyroid adenomas (87.3%) were lower than those for GATA-3. At the same time, all thyroid-derived tumours were positive for TTF-1 and negative for GATA-3, PTH, and chromogranin A. LBC smears of 35 parathyroid lesions indicated that the positive rates for GATA-3, PTH, and chromogranin A were 97.1 %, 97.1%, and 100%, respectively, while in conventional smears, those for PTH (25.5%) and chromogranin A (78.7%) were significantly lower (p < 0.01). Our results suggest that GATA-3 is a more reliable biomarker than PTH or chromogranin A in differentiating parathyroid from thyroid lesions in cytology smears and that LBC is useful in detecting cytoplasmic antigens such as PTH and chromogranin A.

Differentiating between benign follicular nodules and follicular neoplasms in thyroid liquid-based cytology preparations

The cytological morphology observed in liquid‐based cytology (LBC) preparations is dissimilar to that of conventional preparations. The aim of this report is to clarify the cytological differences between benign follicular nodules (BFNs) and follicular neoplasms (FNs) in LBC preparations and identify novel diagnostic criteria for LBC preparations.

Sonographic Evaluation of Nodules Newly Detected in the Neck After Thyroidectomy: Suture Granuloma Versus Recurrent Carcinoma

Purpose This study aimed to clarify the sonographic features of suture granuloma and recurrent carcinoma newly detected after thyroidectomy. Materials and Methods We retrospectively analyzed ultrasound reports with images of 25 cases of suture granuloma and 18 cases of recurrent carcinoma that newly appeared in the resected area after thyroidectomy in our institution. Results Both suture granulomas and recurrent carcinomas more frequently exhibited multiple lesions rather than solitary lesions. Suture granulomas tended to appear in the more superficial areas than the carotid artery, while recurrent carcinomas were more common between the trachea and carotid artery. A total of 10 of the 11 suture granulomas that we followed up decreased in size. Recurrent carcinomas showed irregular shape (55.6%), taller-than-wide shape (38.9%), low internal echogenicity (83.3%), and no punctate microcalcifications. By contrast, suture granulomas were fusiform in shape (56.0%) and showed linear internal echo parallel to the tissue plane on the longitudinal scan (64.0%). The vascular flow sign was mild to none in the majority of both lesions. Conclusion Fusiform shape and linear internal echoes indicate suture granuloma, while irregular shape, taller-than-wide shape, and low echogenicity indicate recurrent carcinoma. Given that the clinical management of suture granuloma differs from that of recurrent carcinoma, it is important to distinguish between these two lesions.

Re-Evaluation of 162 Malignant Thyroid Nodules that were Interpreted as Benign Based on Ultrasound Findings

Purpose The goal of this study was to estimate the risk of malignant thyroid nodules being interpreted as benign based on ultrasound findings and to clarify the pathological features of these malignant nodules. Materials and Methods We retrospectively re-evaluated ultrasound and pathological findings for 162 malignant thyroid nodules that were initially interpreted as benign based on ultrasound findings at Kuma Hospital between April 2012 and June 2015. Results The incidences of malignancy among “benign” thyroid nodules were 0.5% overall and 6.2% among resected nodules. In addition, 82.7% of thyroid nodules that were originally judged to have low or very low suspicion patterns were subsequently re-categorized as having high or intermediate suspicion patterns. The incidences of irregular margins (63.6%) and low echogenicity (36.4%) were higher than those of punctate microcalcification (17.9%) and the taller-than-wide shape (20.4%). Among microcarcinomas, the incidences were 65.7% for irregular margins and 51.4% for low echogenicity. Rim calcification with small extrusive soft tissue components and extrathyroidal extensions were not observed. After re-evaluation, 40.0% of papillary thyroid carcinomas remained benign based on their variants, such as the encapsulated, follicular, macrofollicular, and oxyphilic cell variants. Conclusion We conclude that more careful observation, especially for lesions with irregular margins and low echogenicity, can help improve the diagnostic accuracy of thyroid ultrasonography. Furthermore, greater care may decrease the incidence of malignancy among thyroid nodules with low or very low suspicion patterns. Some variants of papillary thyroid carcinoma can have benign ultrasound findings.

Phantom Nodules Detected by Ultrasound Examination of the Neck: The Possibility of Ectopic Cervical Thymic Tissue in Adults

Purpose The aim of this study was to investigate the ultrasound characteristics and clinical significance of slightly hyperechoic lesions, referred to as phantom nodules, in the perithyroidal area in patients. Materials and Methods A total of 128 patients who underwent thyroidectomy with central neck lymph node dissection at Kuma Hospital in Hyogo, Japan were included in the study. We detected 16 phantom nodules during preoperative ultrasound examinations, defined as slightly hyperechoic masses located in the perithyroidal areas, in 13 of these 128 patients (10.2%; mean age: 55.6 years, range: 36–75 years). Results All phantom nodules were located in the caudal region of the thyroid gland, and the mean maximum dimension was 7.2 mm. 12 of the 16 nodules were round or oval, while the remaining 4 were fusiform and molded by the surrounding tissue. All nodules were well-defined, solid, homogeneous, hyperechoic masses. No speckled echo pattern, internal linear echo, or vascular flow signal was observed. All 4 nodules subjected to histological examination were composed of ectopic thymic tissue. In 2 of these 4, the parenchyma was severely involuted and almost entirely replaced by adipose tissue. Conclusion To the best of our knowledge, this is the first report wherein some of the detected hyperechoic perithyroidal masses were composed of ectopic thymic tissue, and some were primarily composed of adipose tissue that completely replaced involuted ectopic thymic tissue. The results of the study suggest that these so-called phantom nodules are clinically insignificant and do not require fine needle aspiration cytology or further investigation.