纺锤细胞/硬化型横纹肌肉瘤（SSRMS）是一种临床病理学和分子学异质性疾病。在骨内SSRMS中已经发现了基因融合，主要包括EWSR1/FUS::TFCP2和MEIS1::NCOA2。前者通常呈现具有侵袭性疾病进展的临床过程；至于后者，目前临床随访有限。我们在此报告一例新的罕见骨内SSRMS患者，其具有MEIS1::NCOA2基因融合，并详细描述其治疗过程以及52个月的临床随访情况。具有MEIS1::NCOA2基因融合的SSRMS在生物学上与其他骨内SSRMS有明显区别，呈现出局部复发的病程特点，极少有报告表明转移的情况。

Spindle cell/sclerosing rhabdomyosarcoma (SSRMS) is a clinicopathologically and molecularly heterogeneous disease. Gene fusions have been identified in intraosseous SSRMS, consisting predominantly of EWSR1/FUS::TFCP2 and MEIS1::NCOA2. The former often follow an aggressive clinical course; there is limited clinical follow-up available for the latter. We report here a new case of the very rare intraosseous SSRMS with MEIS1::NCOA2 gene fusion and include the detailed treatment course and 52 months of clinical follow-up. SSRMS with MEIS1::NCOA2 gene fusion appears biologically distinct from other intraosseous SSRMS, following a course characterized by local recurrence with rare reports of metastasis to date.