Molecular Pathological Characteristics of Thyroid Follicular-Patterned Tumors Showing Nodule-in-Nodule Appearance with Poorly Differentiated Component.

Thyroid follicular-patterned tumors (TFTs) showing nodule-in-nodule (NN) appearance with poorly differentiated component (PDc) but neither invasion nor metastasis are diagnosed as benign nodules. Although PDc exhibits histologically aggressive features relative to the outer nodule (Out-N), its pathological significance remains unclear. TP53 binding protein-1 (53BP1) is a DNA damage response (DDR) molecule that rapidly localizes at DNA double-strand breaks. Using dual-color immunofluorescence with Ki-67, the profile of 53BP1 expression is shown to be significantly altered during diverse tumorigenesis. In this study, we aimed to elucidate the malignant potential of PDc at the molecular level. We analyzed the profile of 53BP1 expression and NRAS codon 61 and TERT-promoter (TERT-p) mutations in 16 cases of TFTs showing NN with PDc compared to 30 adenomatous goiters, 31 follicular adenomas, 15 minimally invasive follicular carcinomas (FCs), and 11 widely invasive FC cases. Our results revealed that the expression level of abnormal type 53BP1 and incidence of NRAS and TERT-p mutations in PDc were comparable to FCs, suggesting a malignant potential. Because co-expression of 53BP1 and Ki-67 can be an indicator of altered DDR, the development of PDc in NN may be associated with DDR impairments after harboring NRAS and TERT-p mutations.

Pulmonary wedge aspiration cytology for the rapid diagnosis of pulmonary tumor thrombotic microangiopathy: A case report.

Pulmonary tumor thrombotic microangiopathy (PTTM) is a cancer-related pulmonary complication characterized by rapid progression of dyspnea and pulmonary hypertension, occasionally causing sudden death. Given the condition of patients with dyspnea, lung biopsies are limited because of their invasiveness. A 72-year-old man presented with chronic atrial fibrillation and a high right heart load, as determined using ultrasonography. He had previously undergone resection of the left axillary skin secondary to extramammary Paget's disease (EMPD). Clinically, PTTM was suspected and pulmonary wedge aspiration cytology, collected from the pulmonary artery during catherization, was performed. Cytologically, the tumor demonstrated three-dimensional cell clusters with good cohesion and molding by the blood vessel lumen. Additionally, endothelial-like cells were observed at the periphery of the tumor clusters; fibrin was evident in the clusters. The tumor cells were large, round, and had high nuclear/cytoplasmic ratios. The nuclei demonstrated a variety of sizes and were irregularly shaped, with prominent nucleoli; cells undergoing mitosis were evident. The tumor cells were suspected of being poorly differentiated adenocarcinoma cells, consistent with PTTM. Two days after the aspiration cytology, the patient died and a pathological autopsy was performed. Histologically, the PTTM was determined to have caused the pulmonary hypertension and the primary PTTM site was apparently derived from the EMPD. For rapid diagnoses, an understanding of the tumor's cytological features is important and should contribute to early treatment intervention. Aspiration cytology, using pulmonary artery blood samples, during catherization is a useful tool for diagnosing PTTM.

Immunohistochemical Reactivity of Prostate-Specific Markers for Salivary Duct Carcinoma.

OBJECTIVES: NKX3.1, a transcription factor related to androgen expression, has recently been introduced as a diagnostic marker of prostate adenocarcinoma. Salivary duct carcinoma (SDC) is typically positive for androgen receptor (AR). Therefore, we hypothesized that NKX3.1 is a new immunohistochemical marker for SDC and aimed to investigate whether NKX3.1 staining in combination with other immunomarkers of prostate carcinoma could have a diagnostic or prognostic value in SDC. METHODS: Materials obtained from 42 resected SDCs were examined by immunohistochemistry using antibodies against AR, NKX3.1, α-methylacyl-CoA racemase (AMACR), prostatic acid phosphatase (PAP), and prostate-specific antigen (PSA). RESULTS: In immunoreactivity among SDC cases, 81.0, 35.7, 58.5, 33.3, and 0% were positive for AR, NKX3.1, AMACR, PAP, and PSA, respectively. AMACR and PAP immunoreactivity rates were higher in recurrence cases than in cases with no recurrence. CONCLUSIONS: NKX3.1 expression is useful for SDC diagnosis, but decreased NKX3.1 expression was not correlated with SDC progression. The immunoreactivity of AMACR and PAP could be useful for assessing prognosis in SDC, but immunohistochemical staining of prostate-specific markers should be interpreted with caution when determining whether a metastatic tumor is of prostate origin, especially when patients have a history of SDC.

Cribriform-Morular Variant of Papillary Thyroid Carcinoma Shows High Ki-67 Labeling Indices, despite Its Excellent Prognosis.

OBJECTIVE: This study aimed to demonstrate that the cribriform-morular variant (CMV) of papillary thyroid carcinoma (PTC) has high Ki-67 labeling indices, despite its excellent prognosis. METHODS: We examined 21 CMV-PTCs and 5 conventional PTCs (C-PTCs) resected at Kuma Hospital between 2008 and 2018. All of the patients with CMV-PTC were women. Their ages ranged from 17 to 35 years, with a mean of 25.2 years. An immunohistochemical study using ß-catenin, estrogen receptor (ER), and Ki-67 was performed. For apoptotic analysis, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining was performed. RESULTS: All CMV-PTCs were encapsulated with thick fibrous connective tissue. Eleven and one CMV-PTCs exhibited capsular invasion and extrathyroidal invasion, respectively. Two patients showed regional nodal metastasis. The Ki-67 labeling index ranged from 4.8 to 36.4% (mean 15.2%). Apoptotic cells were counted, which showed 2-52 positive cells (mean 12.6) per 10 high-power fields. The Ki-67 labeling index was positively correlated with the apoptotic cell count (r = 0.48, p = 0.030). Ki-67 labeling indices of CMV-PTCs were significantly higher than those of C-PTCs (p = 0.0027). Ages and tumor sizes did not have significant correlations with Ki-67 labeling indices or apoptotic cell counts. CONCLUSION: This study is the first to demonstrate disproportionally high Ki-67 labeling indexes in a large number of CMV-PTC cases, despite the fact that these cases had favorable prognoses. The favorable prognosis of CMV-PTC may be attributable to encapsulation and nuclear ER expression.

Flow cytometric, gene rearrangement, and karyotypic analyses of 110 cases of primary thyroid lymphoma: a single-institutional experience in Japan.

Ancillary studies for primary nodal lymphomas have been well documented; however, studies of primary thyroid lymphoma (PTL) are limited. Here, we aimed to clarify the clinicopathological, flow cytometric, gene rearrangement, and karyotypic characteristics of PTL by investigation of a large series at a single institute. We performed flow cytometric, IgH rearrangement, and karyotypic analyses of 110 PTL tissues surgically resected at Kuma Hospital between January 2012 and April 2017. All PTLs were of B-cell origin, including mucosa-associated lymphoid tissue lymphoma (MALTL; 89 patients, 80.9%), diffuse large B-cell lymphoma (DLBCL; 18 patients, 16.4%), and follicular lymphoma (FL; three patients, 2.7%). In 96 (87.3%) patients, anti-thyroid antibodies were positive. For flow cytometry using aspirated and resected materials, light chain restriction was observed in 73.7% and 69.2% of examined cases, respectively. Heavy chain JH DNA rearrangement was observed in 65.4% of PTLs (58.1% of MALTL cases, 100% of DLBCL cases, and 100% of FL cases). Chromosomal abnormalities were detected in 49.0% of PTLs, and translocation was most frequently detected (24.0%), followed by addition (20.8%) and trisomy (18.8%). The most frequent (9.4%) karyotype was t(3;14)(q27;q32). Both FLs harbored t(14;18)(q32;q21), and the karyotype was not detected in patients with MALTL and DLBCL. The negative rate for all three examinations was 3.8%. We concluded that thyroid MALTL was cytogenetically different from that in other organs. Our results suggested that pre-operative flow cytometry analysis using aspirated materials was as reliable as that using resected materials.

Immunohistochemical and Molecular Analyses Focusing on Mesenchymal Cells in Papillary Thyroid Carcinoma with Desmoid-Type Fibromatosis.

OBJECTIVE: This study was designed to evaluate the prevalence of CTNNB1 (ß-catenin) mutations in cases of papillary thyroid carcinoma with desmoid-type fibromatosis (PTC-DTF) expressing aberrant nuclear and cytoplasmic immunoreactivity for ß-catenin. METHODS: Eight cases of PTC-DTF were available for this study. Immunohistochemistry for ß-catenin and BRAFV600E was performed. CTNNB1 and BRAFV600E mutations were also evaluated by direct sequencing. RESULTS: For ß-catenin, although we could demonstrate aberrant nuclear and cytoplasmic immunoreactivity in DTF components in all cases, suggesting activated Wnt signaling, direct sequencing revealed a missense mutation, c.121A>G (p.T41A), in exon 3 in only one case, and no mutations in exons 3, 4, and 5 in the other cases. In the BRAFV600E analyses, immunohistochemistry revealed positive staining in the carcinoma cells but not DTF components of all cases. These findings were subsequently validated by direct sequencing. CONCLUSION: This study suggests the significance of the BRAFV600E mutation and activation of Wnt signaling pathway in the carcinoma cells and DTF components, respectively. We believe that the CTNNB1 mutations are not the major factor behind ß-catenin translocation indicating Wnt pathway activation. Further study is required to evaluate whether molecular abnormalities other than the CTNNB1 mutation cause activation of Wnt signaling in DTF components of PTC-DTF.

Can Ultrasound Alone Predict Papillary Thyroid Carcinoma with Desmoid-Type Fibromatosis? A Retrospective Analysis of 13 Cases, Focusing on the Stromal Area.

PURPOSE: Papillary thyroid carcinoma with desmoid-type fibromatosis (PTC-DTF) is extremely rare. So far, only 4 cases describing the ultrasound findings of this variant have been reported. Here, we describe the ultrasound findings of 13 cases of PTC-DTF, focusing especially on the DTF area. MATERIALS AND METHODS: We retrospectively analyzed the clinical reports, ultrasound reports, and ultrasound photographs obtained from medical records at Kuma Hospital. RESULTS: The patients included 8 women and 5 men with a mean age of 47.9 years. The widest dimension of the nodules ranged from 16 to 79 mm (mean: 37.5 mm). The original ultrasound reports classified the nodules as either intermediate suspicion or high suspicion. A diagnosis of PTC was suspected in 12 nodules, and anaplastic carcinoma was suspected in 1 nodule. PTC-DTF presented with an irregularly shaped nodule (100%), taller-than-wide sign (84.6%), heterogeneous echogenicity (100%), no microcalcification (76.9%), and no or mild flow signal on Doppler (75.0%). The DTF area was identified in the ultrasound photographs of 8 nodules. DTF areas were generally heterogeneous (62.5%) and more hypoechoic (71.4%) than PTC areas. Microcalcification was not observed in the DTF areas. All of the DTF areas revealed no or mild flow signal. On ultrasound elastography, the DTF areas were not stiff, and they were more elastic than the PTC areas. CONCLUSION: It is difficult to predict PTC-DTF using ultrasound alone, and B-mode ultrasonography is more reliable than ultrasound elastography in the ultrasound diagnosis of malignant thyroid nodules.

Utility of monoclonal PAX8 antibody for distinguishing intrathyroid thymic carcinoma from follicular cell-derived thyroid carcinoma.

Follicular cell-derived thyroid carcinomas, including thyroid squamous cell carcinomas (SCCs) and anaplastic carcinomas, are immunoreactive for paired-box gene 8 (PAX8), while non-follicular cell-derived thyroid carcinomas stain negative for the PAX8 antibody. Intrathyroid thymic carcinoma (ITTC) arising from the intrathyroidal ectopic thymus exhibits moderate-to-strong nuclear reactivity for polyclonal PAX8. This is difficult to understand given that PAX8 is not associated with embryonic thymic development. We aimed to determine the diagnostic significance of monoclonal PAX8 antibody in distinguishing ITTCs from follicular cell-derived thyroid carcinomas. Ten ITTCs, 14 poorly differentiated thyroid carcinomas (PDTCs), 14 thyroid SCCs, 7 thymic tissue specimens, 7 thymomas, and 1 thymic carcinoma were analyzed using antibodies against polyclonal and monoclonal PAX8, thyroid transcription factor-1, p63, and CD5. Four ITTCs (40.0%) stained positive for polyclonal PAX8; none stained positive for monoclonal PAX8. All PDTCs and 92.9% of SCCs were immunoreactive for both polyclonal and monoclonal PAX8. All PDTCs, 46.2% of SCCs, and none of the ITTCs were immunoreactive for thyroid transcription factor-1. Eight ITTCs (80.0%), but none of the PDTCs and SCCs, were immunoreactive for CD5. We are the first to show that ITTCs stain negative for monoclonal PAX8. Monoclonal PAX8 is a more reliable marker than polyclonal PAX8 for determining follicular cell origin. We conclude that monoclonal PAX8 is a useful marker for distinguishing ITTCs from PDTCs and SCCs. Monoclonal PAX8 negativity is additional evidence in support of ITTCs not being follicular cell-derived thyroid carcinomas, but having a thymic origin.

Derivation of thyroid lymphoepithelial cysts from follicular cells.

The pathogenesis of thyroid lymphoepithelial cysts is controversial, and two hypotheses have been proposed, namely derivation from branchial-derived remnants or from squamous metaplasia of the follicular cells. The aim of this study was to clarify the pathogenesis of thyroid lymphoepithelial cysts. We performed pathological and immunohistochemical examination of 21 thyroid lymphoepithelial cysts, 13 non-neoplastic squamous metaplasia samples without thyroid carcinoma, 13 solid cell nests, and 14 lateral cervical cysts. On ultrasound, half of thyroid lymphoepithelial cysts were interpreted as calcified nodules regardless of no calcification. Thyroid lymphoepithelial cysts and squamous metaplasia tended to be located in the central and lower portions of the thyroid, while solid cell nests were located in the upper and central portions (p < 0.05). In 95.2% of patients with thyroid lymphoepithelial cysts and all patients with squamous metaplasia, lesions were histologically associated with chronic thyroiditis forming lymph follicles. Hashimoto's disease was serologically confirmed in 18 patients with lymphoepithelial cysts (85.7%) and 10 patients with squamous metaplasia (76.9%). Immunohistochemically, lymphoepithelial cysts showed nuclear positivity for PAX8, thyroid transcription factor 1, and p63. One lateral cervical cyst (7.1%) showed positive staining for PAX8, while solid cell nests were PAX8-negative. In three (14.3%) cases of thyroid lymphoepithelial cysts, squamous cells located on the superficial layer were focally and weakly positive for CEA. We concluded that thyroid lymphoepithelial cysts originate from follicular cells and are unrelated to solid cell nests and lateral cervical cysts arising from branchial-derived remnants.

Identification of Cytological Features Distinguishing Mucosa-Associated Lymphoid Tissue Lymphoma from Reactive Lymphoid Proliferation Using Thyroid Liquid-Based Cytology.

OBJECTIVE: To identify cytological differences between mucosa-associated lymphoid tissue lymphoma (MALT-L) and nonneoplastic lymphocytes using thyroid liquid-based cytology (LBC). STUDY DESIGN: We observed LBC and conventional specimens from 35 MALT-L cases, 3 diffuse large B-cell cell lymphoma (DLBCL) cases, and 44 prominent nonneoplastic lymphocytic infiltration cases. RESULTS: In MALT-L cases, the incidence of lymphoglandular bodies in the LBC specimens was lower than that in the conventional specimens (p < 0.001). Moreover, the nuclear sizes in LBC specimens were larger than those in conventional specimens. In 62.9% of the MALT-L and all DLBCL specimens, large nuclei were present in > 10% of the lymphoid cells in LBC specimens. Two cases with prominent nonneoplastic lymphocytic infiltration also exhibited these findings. In LBC specimens, swollen naked nuclei with less punctate chromatin patterns and thin nuclear margins were observed in 92.1% of lymphoma and 20.5% of prominent nonneoplastic lymphocytic infiltration. Elongated nuclei were significantly more apparent in thyroid lymphoma than in prominent nonneoplastic lymphocytic infiltration (p < 0.001), with a significantly higher incidence in LBC specimens than in conventional specimens (p < 0.001). CONCLUSIONS: Lymphoglandular bodies are not reliable markers for lymphoma diagnosis using LBC specimens. Large, swollen naked, and elongated nuclei are useful in distinguishing thyroid lymphoma from nonneoplastic lymphocytes in LBC specimens.

Thyroid sclerosing mucoepidermoid carcinoma with eosinophilia distinct from the salivary type.

We report three cases of thyroid sclerosing mucoepidermoid carcinoma with eosinophilia (SMECE), which is an extremely rare variant of mucoepidermoid carcinoma (MEC). The aims of this report were to describe the clinicopathological findings, including results from immunohistochemical and fluorescence in situ hybridization analysis of thyroid SMECE, as well as to discuss the distinction between thyroid SMECE and its salivary counterpart. The cases included a 63-year-old female, a 44-year-old male, and a 66-year-old female, with all patients presenting with Hashimoto's thyroiditis. Nodal metastasis was not found in any of the three cases. Neither regional recurrences nor distant metastases were found in any patient during the follow-up, which was 20 years, 3 years, and 18 months, respectively. Histologically, tumors were composed of epidermoid carcinoma cells, intermediate type carcinoma cells, and goblet cell-type mucus-secreting carcinoma cells, with all tumors displaying a sclerotic stroma with eosinophilic and lymphocytic infiltration. The formation of eosinophilic abscess in the tumor nests that might be a novel characteristic finding of SMECE was observed. Immunohistochemically, the carcinoma cells were positive for cytokeratin 34ßE12, TTF-1, and PAX8, but negative for thyroglobulin. In two cases, increased IgG4-positive plasma cells were observed. Mastermind-like transcriptional coactivator 2 (MAML2), according to fluorescence in situ hybridization, was intact in all cases. In conclusion, thyroid SMECE has favorable outcomes and seems to be genetically different from salivary MEC. This is the first report to describe the presence of increased IgG4-positive plasma cells in the stroma of SMECE.

Re-evaluation of MIB-1 immunostaining for diagnosing hyalinizing trabecular tumour of the thyroid: semi-automated techniques with manual antigen retrieval are more accurate than fully automated techniques.

Hyalinizing trabecular tumour (HTT) immunohistochemically shows cell membranous immunoreactivity for MIB-1. This aberrant immunoreactivity is an important factor for the diagnosis of HTT. However, fully automated stainers frequently fail to confirm the immunoreactivity. The aim of this study is to investigate the cause of false negative cell membranous immunoreactivity for MIB-1 in HTT using fully automated stainers, to determine potential reasons for the problem, and to establish methods confirming cell membranous immunoreactivity for MIB-1 in HTT. Six participating institutions examined immunoreactivity for MIB-1 in 10 HTT cases using two approaches: fully automated and semi-automated methods. In the latter, antigen retrieval was carried out using manual methods adopted for routine assays at each institute. The autostainers used included the BOND-MAX, BOND-III, Benchmark XT, and Omnis systems. Using fully automated methods, institute E showed cell membranous MIB-1 positivity in all HTT cases. In contrast, at institute D, all HTT cases were negative. The positive rates of the remaining four institutes ranged from 10% to 20%. The incidence of positive cases using semi-automated methods was 100%, 90%, 90%, 30%, 80%, and 100% at institutes A, B, C, D, E, and F, respectively. We assert that antigen retrieval should be conducted manually for diagnosis of HTT; furthermore, definitively diagnosed HTT should be prepared as the external positive control.

Warthin-like papillary thyroid carcinoma with immunoglobulin G4-positive plasma cells possibly related to Hashimoto's thyroiditis.

Hashimoto's thyroiditis with heavy lymphoplasmacytic infiltration is a common comorbidity of immunoglobulin G4 (IgG4)-related thyroiditis and Warthin-like papillary thyroid carcinoma (WL-PTC). We hypothesized that WL-PTC may have a strong association with IgG4-related thyroiditis. To validate this hypothesis, we clinically and immunohistochemically studied 17 WL-PTC cases. Fourteen patients (82.4%) had anti-thyroglobulin antibody and were confirmed to have Hashimoto's thyroiditis through microscopic analysis. Among them, five (29.4%) had disease consistent with IgG4-related thyroiditis but did not exhibit a "storiform" pattern or obliterative phlebitis. IgG4-related diseases were not found in other organs. No cases with serum IgG4 level of >135 mg/dL were noted. A total of 94.1% of WL-PTC cases had IgG4-positive plasma cells (+PCs) in the stroma, and cases with rich IgG4+PCs were more frequently associated with Hashimoto's thyroiditis than those with poor IgG4+PCs. In this study, all three cases without Hashimoto's thyroiditis had poor IgG4+PCs, and one of them did not exhibit IgG4+PCs in the stroma of WL-PTC and Hashimoto's thyroiditis. Nodal metastatic lesions were seen in eight cases, all of which were not WL-PTC. As such, we should consider that the Hashimoto's disease with rich IgG4+PCs seen in our cases is representative of non-IgG4-related disease and not IgG4-related disease involving multiple organs. This study is the first to demonstrate the presence of IgG4+PCs in the stroma of WL-PTC. We concluded that the appearance of IgG4+PCs in the stroma of WL-PTC may be related to Hashimoto's thyroiditis with rich IgG4+PC.

Fine-needle aspiration cytology for medullary thyroid carcinoma: a single institutional experience in Japan.

Many cytological studies on medullary thyroid carcinoma (MTC) have been reported; however, such studies in large series of patients with MTC have not been performed. We investigated MTC at a single institution in Japan using fine-needle aspiration cytology (FNAC), and aimed to establish a preoperative diagnostic algorithm for MTC. FNAC was performed in 119 of 149 patients with MTC (79.9%) who ultimately underwent surgical resection. Moreover, 22 of 56 hereditary MTC (39.3%) were diagnosed preoperatively without FNAC by their high serum calcitonin levels or increased response to calcium stimulation (11 cases each), as well as RET mutation analysis. On FNAC, 76.5% of nodules were categorized as 'malignancy' or 'suspicious for malignancy'. The sensitivity and specificity of calcitonin measurement in aspiration needle wash-out fluid and in immunocytochemical staining for calcitonin were 96.3% and 92.3% respectively. We proposed an algorithm for preoperative diagnosis of MTC utilizing FNAC: When thyroid nodules are highly suspicious for MTC by their clinical and ultrasonographic features, serum calcitonin measurement with or without a calcium stimulation test is required. Furthermore, FNAC should be performed for patients who do not have those findings. When there is a possibility of MTC at the time of FNAC, calcitonin measurement using needle wash-out fluid is a reliable diagnostic tool. When MTC is suspected on cytological examination, immunocytochemical staining for calcitonin is useful for confirming MTC diagnosis.

Papillary thyroid carcinoma with desmoid-type fibromatosis: A clinical, pathological, and immunohistochemical study of 14 cases.

Papillary thyroid carcinoma (PTC) with desmoid-type fibromatosis (DTF) is characterized by genetic alterations of the fibroblasts. PTC-DTF is extremely rare, and the reports on such cases have been sporadic. Immunohistochemical staining using the antibody for beta-catenin is useful in diagnosing the variant. This report aims to describe the clinical, pathological, and immunohistochemical findings in 14 cases of PTC-DTF and to clarify the diagnostic significance of the variant. The patients included 9 women and 5 men, with a mean age of 49.3 years. PTCs with focal DTF components and with extensive DTF components included 7 cases each. No significant differences were noted in terms of age, gender, and serum thyroglobulin levels between extensive and focal DTF cases. On aspiration cytology, 12 cases were reported as suspicious for malignancy or malignant, and schwannoma or fibroma was suggested in 1 case each. The DTF components were histologically classified into 4 types, namely, central (4 cases), peripheral (1 case), mixed (7 cases), and diffuse type (2 cases). The stromal components were consistent with those of DTF. Immunohistochemically, fibroblasts in the DTF components showed nuclear and cytoplasmic expression for beta-catenin in 12 cases. The features are observed even in cases in which stromal components focally exist. Neither carcinoma cells nor the fibroblasts with Ki-67 labeling index >5% were found in all cases. We agree that PTC with nodular fasciitis-like stroma should be renamed to PTC-DTF.

Cytoplasmic Lipid Accumulation Characteristic of the Cribriform Variant of Papillary Thyroid Carcinoma.

OBJECTIVE: The purpose of this study was to clarify the diagnostic significance of cytoplasmic lipid accumulation (CLIA) in the cribriform variant of papillary thyroid carcinoma (CV-PTC). METHODS: We performed a histological, immunohistochemical, and cytological examination of 35 CV-PTC cases at the Kuma Hospital. CLIA was defined as bubble-like multivacuolation in cytoplasm with distinct cell border. We also examined 100 conventional PTC (con-PTC) cases as controls. RESULTS: Histological analysis showed the presence of carcinoma cells with CLIA in 60.0% of CV-PTC and 5.0% of con-PTC cases. The vacuoles tended to distribute in the subnuclear portion of carcinoma cells showing papillary growth. They were positive for oil red O staining and adipophilin. The carcinoma cells without the vacuoles showed a subnuclear dot-like expression for adipophilin in CV-PTC cases, but not in the con-PTC cases. Cytological analysis showed CLIA in 17 (54.8%) of the 31 CV-PTC cases, but not in the con-PTC cases. CONCLUSION: This is the first study to report the presence of carcinoma cells with CLIA in CV-PTC. The subnuclear dot-like expression of adipophilin may be characteristic of CV-PTC. These findings might be related to degenerative changes occurring in CV-PTC.

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.

A Novel Germline Mutation of KEAP1 (R483H) Associated with a Non-Toxic Multinodular Goiter.

BACKGROUND: A germline mutation of KEAP1 gene was reported as a novel genetic abnormality associated with familial multinodular goiter. That report was limited, and the pathogenic features were not well established. PATIENT FINDINGS: We report a 47-year-old Japanese woman who presented with hyperthyroidism and a large multinodular goiter. The family history was notable for a paternal history of goiter. Graves' disease was diagnosed based on positive TRAb, but scintiscan imaging showed that the patient's radioiodine uptake was restricted in the non-nodular areas, indicating largely cold nodules. A total thyroidectomy was performed. The resected thyroid tissue weighed 209 g, and subsequent pathological findings were benign. The patient had a germline heterozygous KEAP1 mutation, c. 1448 G > A, resulting in an amino acid substitution (p.R483H). A next-generation sequencing analysis covering all known genes associated with multinodular goiter showed no additional germline mutation. The nuclear accumulation of NRF2, a protein associated with KEAP1, was shown at much higher rates in the patient's nodules compared with nodules obtained from four unrelated patients with multinodular goiters. CONCLUSION: A novel germline mutation (R483H) of KEAP1 gene was associated with the development of a non-toxic multinodular goiter.

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

BACKGROUND: 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. METHODS: A retrospective review of LBC preparations from 38 BFN and 74 FN (57 follicular adenomas and 17 follicular carcinomas) cases confirmed by histological examination was conducted. LBC samples were obtained from the washout fluid in aspiration needles, fixed with CytoRich-RED(TM) , and prepared using the SurePath(TM) method. RESULTS: Fibrin was observed in 43.2% of FNs and in 23.7% of BFNs. The incidences of intercellular spaces, distinct outer margin, and cytoplasmic process were significantly higher in BFNs (P < 0.01, P < 0.01, and P < 0.05, respectively). Elongated microfollicles were seen in 55.4% of FNs and 10.5% of BFNs (P < 0.01). Membranous materials encircling the outer edge of the follicles were observed only in BFN cases (5.8%). There were no significant differences between follicular adenoma and carcinoma. CONCLUSION: Intercellular spaces, distinct outer margins of the follicular clusters, cytoplasmic process, and membranous materials constitute indicators of BFN in LBC preparations. Fibrin and elongated microfollicles point to FN. We believe that these findings will improve the diagnostic accuracy of thyroid LBC preparations. Diagn. Cytopathol. 2016;44:659-664. © 2016 Wiley Periodicals, Inc.

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.