Sugawara Masato, Kobayashi Eisuke, Asano Naofumi, Yoshida Akihiko, Kawai Akira
1 Department of Musculoskeletal Oncology, National Cancer Center Hospital, Tokyo, Japan.
2 Department of Orthopaedic Surgery, Yamagata University, Faculty of Medicine Yamagata, Japan.
Int J Surg Pathol. 2017 Oct;25(7):629-634. doi: 10.1177/1066896917709580. Epub 2017 May 16.
The histological diagnosis of malignant peripheral nerve sheath tumor (MPNST) is challenging because of the wide morphological spectrum and suboptimal performance of conventional immunohistochemical markers. MPNST arising primarily in the bone is exceptional, and its definitive diagnosis, particularly out of the neurofibromatosis type 1 (NF1) context, is even more problematic. Recurrent inactivation of EED or SUZ12 in a majority of MPNSTs results in a complete loss of trimethylated histone H3 at lysine 27 (H3K27me3) immunoreactivity, making it a highly specific biomarker of MPNSTs. In this article, we report a case of sporadic MPNST of the proximal femur that showed complete loss of H3K27me3. The patient was treated with limb-sparing surgery and postoperative radiotherapy. He developed multiple lung and bone metastases 4 months after surgery. Our case confirms the utility of H3K27me3 immunohistochemistry to yield a definitive diagnosis of sporadic MPNST in a rare primary site.
恶性外周神经鞘瘤（MPNST）的组织学诊断具有挑战性，因为其形态谱广泛且传统免疫组化标志物的性能欠佳。主要起源于骨的MPNST较为罕见，其明确诊断，尤其是在非1型神经纤维瘤病（NF1）背景下，更是存在问题。大多数MPNST中EED或SUZ12的反复失活导致赖氨酸27三甲基化组蛋白H3（H3K27me3）免疫反应性完全丧失，使其成为MPNST的高度特异性生物标志物。在本文中，我们报告了一例股骨近端散发性MPNST病例，该病例显示H3K27me3完全缺失。患者接受了保肢手术和术后放疗。术后4个月，他出现了多处肺和骨转移。我们的病例证实了H3K27me3免疫组化在罕见原发部位散发性MPNST明确诊断中的作用。
