骨外粘液样软骨肉瘤（EMC）是一种罕见的恶性肿瘤，常出现在头颈部位，尤其是牙龈区域。我们报道了一例发生在右下颌牙龈的病例，并对相关文献进行了简要回顾。本病例为24岁男性患者，右侧下颌后牙龈处有一直径为3.5×2.0cm的病变，持续2个月。肿瘤由软骨结构和黏液样基质组成。免疫组化（IHC）显示肿瘤细胞对波形蛋白呈阳性表达，局部对S-100呈阳性表达，对卡尔波宁、SMA、SOX10呈阴性表达。Ki-67标记指数为80%。荧光原位杂交（FISH）检测结果显示NR4A3基因重排呈阳性。由于其在口腔区域的不寻常位置和低发病率，在临床诊断和治疗过程中应考虑组织学特征、免疫组化和分子病理学以及与其他疾病的鉴别诊断的综合分析。 © 2023. BioMed Central Ltd., Springer Nature的一部分。

Extraskeletal myxoid chondrosarcoma (EMC) is a rare malignant tumor described in the head and neck region, especially in the gingival. We present one case arising in the gingival of right mandible, and briefly reviewed the related literature.A 24-year-old male patient with a lesion of 3.5*2.0 cm in buccal gingival of right posterior mandible for 2 months. The tumor was composed of cartilaginous structures and myxoid matrix. Immunohistochemical(IHC) showed that the tumor cells to be positive for vimentin, focally positive for S-100, negative for calponin, SMA, SOX10. The Ki-67 labelling index was 80%. Fluorescent in situ Hybridization (FISH) was positive for NR4A3 rearrangement.Due to its unusual site and low incidence in the oral region, a combination of histological findings, immunohistochemistry, and molecular pathology as well as differential diagnosis with other diseases should be taken into consideration in the process of clinical diagnosis and treatment.© 2023. BioMed Central Ltd., part of Springer Nature.