背景：肺泡软组织肉瘤（ASPS）是一种非常罕见的起源不确定的间充质恶性肿瘤。它主要影响年轻人，大约四分之一的病例被诊断为儿童。
方法：一名11岁女孩在左肘区域有一个无痛的皮下“肿块”。影像学检查显示，肌肉内的软组织肿块可疑。进行了病灶的手术切除。活检由35×20×12毫米的小叶肿瘤组成。组织学显示，上皮样细胞群以类器官假肺泡模式排列。它在免疫组织化学上表达TFE3，并带有ASPSCR1::TFE3基因融合。建立了ASPS的诊断。随后，对瘢痕进行了广泛的再切除，没有显微镜下残留的肿瘤。患者目前没有局部复发或转移的证据。
结论：ASPS被认为是侵袭性和预后不良的化学耐药肿瘤。与成人相比，儿童的预后更好。在完全手术切除的局部阶段早期检测肿瘤仍然是主要的治疗选择。由于其晚期转移的倾向，有必要对患者进行长期彻底的随访.
BACKGROUND: Alveolar soft part sarcoma (ASPS) is a very rare mesenchymal malignancy of uncertain origin. It mostly affects young people, with about a quarter of cases being diagnosed in children.
METHODS: An 11-year-old girl had a painless subcutaneous \"lump\" in the left elbow area. Imaging exams revealed a solid soft-tissue intramuscular mass of suspicious appearance. A surgical excision of lesion was performed. The biopsy consisted of a lobular tumor measuring 35 × 20 × 12 mm. Histology revealed an epithelioid-cell population arranged in organoid pseudoalveolar pattern. It immunohistochemically expressed TFE3 and harbored the ASPSCR1:: TFE3 gene fusion. A diagnosis of ASPS was established. Subsequently, a wide re-excision of the scar was performed without microscopic residual tumor. The patient is currently without evidence of local recurrence or metastasis.
CONCLUSIONS: ASPS is considered an aggressive and prognostically unfavorable chemoresistant neoplasm. Children have a better prognosis compared to adults. Early detection of tumor in a localized stage with complete surgical removal remains a mainstay therapeutic option. Due to its tendency to late metastases, a long-term thorough follow-up of the patient is necessary.
