The term
soft tissue sarcoma
(STS) refers to a rare group of multiple subtypes of cancer that arise in connective tissues, such as fat, muscles, and blood vessels. The disease is known to metastasize rapidly. Herein, we report a case of a 24-year-old female who complained of a painless mass in her right thigh that was gradually growing in size. The patient had lost 11 kg of weight unintentionally. On examination, there was a large mass at the right upper lateral thigh, which was warm and nontender on palpation with relatively well-defined margins clinically. The magnetic resonance imaging (MRI) scan suggested the presence of sarcoma. When biopsied, the histopathological assessment showed neoplastic infiltrates consistent with alveolar soft-part sarcoma (ASPS). There was no evidence of metastasis on computerized tomography (CT). Treatment with preoperative radiation followed by surgery was offered after discussion at the Tumor Board meeting, but the patient opted for surgery alone. This was mainly due to her concerns about the adverse effects of radiotherapy on her fertility. The patient did not develop any postoperative complications. This case highlights the importance of identifying and managing such cases promptly to improve clinical outcomes and aims to contribute to improving understanding of this rare disease.