{"title":"Reevaluating hybrid neurofibroma/schwannoma: Predominance of schwannoma features despite CD34 positivity and initial neurofibroma diagnosis","authors":"Tatsuya Katsumi, Ryota Hayashi, Shingo Takei, Osamu Ansai, Sumiko Takatsuka, Tatsuya Takenouchi, Kyota Saito, Kazuaki Suda, Kosuke Yoshihara, Takahiro Nagai, Shujiro Okuda, Takaya Fukumoto, Shin-ichi Ansai, Anna Nakamura, Koji Katsuumi, Takashi Ariizumi, Akira Ogose, Hiroyuki Kawashima, Riichiro Abe","doi":"10.1111/1346-8138.17343","DOIUrl":null,"url":null,"abstract":"<p>Schwannomas consist of both high-cellularity regions (Antoni A area) and hypocellular regions (Antoni B area) in histopathological findings. Neurofibromas characteristically consist of CD34 positive spindle cells with thin, wavy, nuclei and wavy collagen bands. Previous reports have described segments of schwannomas with neurofibroma features as hybrid tumors, although hybrid tumors were diagnosed based on partial CD34 positivity in many previous reports. On the other hand, the Antoni B area of some schwannomas was reported to be positive for CD34. Therefore, the definition of a hybrid tumor has not been clear. The objective of this study was to determine whether only CD34 positive findings in schwannomas could be used to define a hybrid tumor. In the analysis of our patient with schwannomatosis caused by a novel <i>LZTR1</i> germline mutation, part of the tumor had CD34 positive hypocellular regions. These regions contained no thin, wavy, nuclei, indicating an Antoni B area. Laser microdissection was used to investigate the genetic background and differences in molecular mechanisms between CD34 positive and CD34 negative regions. All mutations identified in CD34 positive regions were also found in CD34 negative regions. Our data could not clear the genetic background of Antoni B which was CD34 positive area. We then reviewed the pathologies of 66 sporadic schwannomas. Histopathological examinations of all schwannomas revealed the absence of thin, wavy, nuclei and wavy collagen bands, and no hybrid tumors were found in any of the cases. Ten of 66 patients were randomly selected for CD34 immunostaining and positivity was found in all cases. Our data suggest that it is difficult to distinguish schwannomas by staining for CD34 alone, as Antoni B areas can also be positive for CD34. Therefore, CD34 staining alone should not be used to diagnose hybrid tumors in patients with schwannomas.</p>","PeriodicalId":54848,"journal":{"name":"Journal of Dermatology","volume":null,"pages":null},"PeriodicalIF":2.9000,"publicationDate":"2024-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Dermatology","FirstCategoryId":"3","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1111/1346-8138.17343","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"DERMATOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Schwannomas consist of both high-cellularity regions (Antoni A area) and hypocellular regions (Antoni B area) in histopathological findings. Neurofibromas characteristically consist of CD34 positive spindle cells with thin, wavy, nuclei and wavy collagen bands. Previous reports have described segments of schwannomas with neurofibroma features as hybrid tumors, although hybrid tumors were diagnosed based on partial CD34 positivity in many previous reports. On the other hand, the Antoni B area of some schwannomas was reported to be positive for CD34. Therefore, the definition of a hybrid tumor has not been clear. The objective of this study was to determine whether only CD34 positive findings in schwannomas could be used to define a hybrid tumor. In the analysis of our patient with schwannomatosis caused by a novel LZTR1 germline mutation, part of the tumor had CD34 positive hypocellular regions. These regions contained no thin, wavy, nuclei, indicating an Antoni B area. Laser microdissection was used to investigate the genetic background and differences in molecular mechanisms between CD34 positive and CD34 negative regions. All mutations identified in CD34 positive regions were also found in CD34 negative regions. Our data could not clear the genetic background of Antoni B which was CD34 positive area. We then reviewed the pathologies of 66 sporadic schwannomas. Histopathological examinations of all schwannomas revealed the absence of thin, wavy, nuclei and wavy collagen bands, and no hybrid tumors were found in any of the cases. Ten of 66 patients were randomly selected for CD34 immunostaining and positivity was found in all cases. Our data suggest that it is difficult to distinguish schwannomas by staining for CD34 alone, as Antoni B areas can also be positive for CD34. Therefore, CD34 staining alone should not be used to diagnose hybrid tumors in patients with schwannomas.
期刊介绍:
The Journal of Dermatology is the official peer-reviewed publication of the Japanese Dermatological Association and the Asian Dermatological Association. The journal aims to provide a forum for the exchange of information about new and significant research in dermatology and to promote the discipline of dermatology in Japan and throughout the world. Research articles are supplemented by reviews, theoretical articles, special features, commentaries, book reviews and proceedings of workshops and conferences.
Preliminary or short reports and letters to the editor of two printed pages or less will be published as soon as possible. Papers in all fields of dermatology will be considered.