MOLECULAR DETECTION OF MECT1-MAML2 FUSION GENE IN MUCOEPIDERMOID CARCINOMA WITH ORDINARY AND VARIANT HISTOLOGY: A STUDY USING ARCHIVAL PARAFFIN EMBEDDED TISSUE

Mucoepidermoid carcinoma (MEC) has been characterized by t (11; 19)(q21; p13). This chromosomal translocation has been recently shown to generate a MECT1- MAML2 fusion gene. MEC can pose diagnostic challenges when they are of high-grade, of variant histologic appearance and occurring in an unusual site. The aim of this study was to evaluate the frequency of the MECT1-MAML2 fusion gene among primary salivary gland MECs and extrasalivary gland MECs, together with some histological variants and its role as a possible diagnostic adjunct, comparing the salivary gland tumors including Warthin's tumor(WT)，pleomorphic adenoma(PA)，and adenoid cystic carcinoma(ACC). Using a reverse transcription-polymerase chain (RT-PCR)-based approach, we assayed for the MECT1-MAML2 transcript in 39 cases for which paraffin- embedded tumor tissue with adequate RNA was available. These included 19 MECs，10 WTs， five PAs， and five ACCs. The MECT1-MAML2 fusion gene transcript was detected in 16 (84.2%) of 19 MECs. These positive cases included two cases of MEC with WT-like areas，a sclerosing MEC and a clear cell MEC. Three negative cases were high- grade MECs. Two of them were not easy to distinguish from squamous cell carcinoma. The MECT1-MAML2 fusion gene was negative in all cases of WT，PA and ACC. The potential usefulness of MECT1-MAML2 fusion gene expression as a molecular marker in the diagnosis of MEC is supported

Hibernoma of the axillary region: a rare benign adipocytic tumor

Hibernoma is a rare benign tumor considered to arise from remnants of fetal brown adipose tissue. It tends to occur in sites where brown fat persists beyond fetal life, such as the interscapular region, but can occur in sites where brown fat is usually absent in adults. Clinicallywell, hibernomas are slow-growing, asymptomatic tumors. However, unlike lipomas, MRI findings sometimes mislead clinicians to diagnose a malignant neoplasm. We describe a 63-year-old male with an axillary hibernoma involving the brachial neurovascular bundles and mimicking a well-differentiated liposarcoma, from which it should be distinguished

腹膜および胸膜悪性中皮腫におけるEGFR発現の比較

An evaluation of epidermal growth factor receptor (EGFR) phenotypic expression in malignant pleural and peritoneal mesothelioma was undertaken, using immunohistochemical (IHC) and fluorescence in situ hybridization (FISH) analysis. Thirty-eight malignant mesothelioma (MM) specimens were subjected to IHC staining and FISH to evaluate the expression of EGFR protein and gene status. Overall positive IHC reaction was detected in 20/38 (53%) cases, in 11/22 (50%) pleural MM, and in 9/16 (56%) peritoneal MM. Our study confirmed that EGFR membranous expression is a common feature in MM, but not in benign mesothelial lesion. Thirty-seven cases did not show a gene copy number gain. Only one case showed a copy number gain. The protein overexpression of EGFR was not related to a gene copy number gain.博士（医学）・乙第1299号・平成24年5月28日© 2012 The Authors. Pathology International© 2012 Japanese Society of Pathology and Blackwell Publishing Asia Pty Ltd

乳腺腺様嚢胞癌においてサイトケラチン5/6の腺腔形成細胞の染色性は類似病変との鑑別に有用である

Adenoid cystic carcinoma (AdCC) of the breast is an uncommon but distinct neoplasm composed of a dual cell population polarized around true glandular (luminal) spaces and pseudolumina. The aim of this study was to clarify whether various immunohistochemical markers (CK7, EMA, CD117, p63, calponin, CD10, S100, CK5/6, CK14, vimentin, and type IV collagen) can distinguish between the two cell types in classical AdCC (n = 14) and in collagenous spherulosis (n = 5). The sensitivity and specificity of these 11 markers to distinguish luminal from abluminal cells were evaluated using a curve created by plotting the true-positive rate (sensitivity) against the false-positive rate (1 - specificity) at threshold settings of 0, 10, 50, and 70 %. The most sensitive and specific markers for luminal cells in AdCC were CK7 and EMA; those for abluminal cells were type IV collagen, p63, and vimentin. CD10 and S100 did not act as abluminal markers in AdCC. CK5/6, one of the basal/myoepithelial markers, was expressed more frequently in luminal than in abluminal cells of AdCC. Thus, CK5/6 immunostaining resulted in a reverse expression pattern, analogous to what we recently documented in clear cells in mammary adenomyoepithelioma. In conclusion, compared with myoepithelial/abluminal cells of normal breast or collagenous spherulosis, the neoplastic abluminal cells of classical AdCC are characterized by enhanced vimentin and attenuated CD10 and S100. Furthermore, the luminal cells of AdCC show a unique aberrant staining pattern for CK5/6 that may aid in the differential diagnosis.博士（医学）・乙第1389号・平成28年11月24日© Springer-Verlag Berlin Heidelberg 2016The final publication is available at Springer via http://dx.doi.org/10.1007/s00428-016-1963-

内視鏡超音波ガイド下穿刺吸引の液状検体の残余を用いたK-ras 遺伝子検査は正診率を高める

Background: Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) technology is widely used for the diagnosis of pancreatic masses. However, in some cases, inadequate tissue volume or difficulty of morphological diagnosis are constraining factors for adequate cytopathological evaluation. K-ras mutation is the most frequently acquired genetic abnormality, occurring in approximately 90% of all patients with pancreatic ductal adenocarcinoma (PDAC). In the present study, the clinical utility of residual liquid-based cytology (LBC) specimens obtained using EUS-FNA for K-ras mutation analysis was evaluated. Methods: In this study, 81 patients with pancreatic lesions were examined. The cell block (CB) specimens separated from EUS-FNA samples were morphologically evaluated by hematoxylin-eosin (HE) staining. Final diagnoses were confirmed by CB specimens, surgical resection specimens, diagnostic imaging, and clinical follow-up. Genomic DNA of residual LBC specimens stored at 4°C for several months were extracted and assessed for K-ras mutations using a fluorescence resonance energy transfer-based preferential homoduplex formation assay. Results: K-ras mutation analysis using residual LBC samples was successful in all cases. The sensitivity, specificity, and accuracy of CB examination alone were 77.4%, 100%, and 81.3%, respectively, and those of the combination of CB examination and K-ras mutation analysis were 90.3%, 92.3%, and 90.7%, respectively. Furthermore, K-ras mutations were detected in 8 (57.1%) of 14 PDAC samples for which the CB results were inconclusive. Conclusion: These findings suggest that K-ras mutation analysis using residual LBC specimens improves the diagnostic accuracy of EUS-FNA.博士（医学）・乙第1492号・令和2年12月24日Copyright: © 2018 Sekita-Hatakeyama et al. This is an open access article distributed under the terms of the Creative Commons Attribution License(https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited