Abstract
Background: Alveolar soft part sarcoma (ASPS) is a very rare mesenchymal malignancy of un-certain origin. It mostly affects young people, with about a quarter of cases being diagnosed in children.
Case: 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 appear-ance.
A surgical excision of lesion was performed. The bio psy consisted of a lobular tumor measuring 35 x 20 x 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-ex-cision of the scar was performed without microscopic residual tumor.
The patient is currently without evidence of local recurrence or metastasis. Conclusion: ASPS is considered an aggre-ssive 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.