Rationale: Alveolar soft part sarcoma (ASPS) is a very rare soft tissue sarcoma. ASPS often occurs in deep soft tissues of the lower extremities, and develops into metastatic diseases. Chemotherapy is considered to be ineffective in patients with ASPS, which constitutes a very important clinical challenge. The strategy for ASPS treatment still requires clarification in order to improve survival outcome. Patients concerns: A 19-year-old female patient presented with a 5-year history of painless lump in the left knee and 4-day cough. Her previous medical history was unremarkable. Menstruation and family history were also normal in this patient, whose physical examination and laboratory test results showed no abnormalities.
Diagnosis: ASPS was confirmed by clinical manifestations, radiological data and pathological diagnosis of the biopsy of left knee.
Interventions and outcomes: This patient received circulating tumor DNA detection and only a mutation of the SMARCA4 gene was detected. The patient received sunitinib treatment (37.5 mg once daily) for 15 months and showed partial regression of lung metastatic lesions and stabilization of brain metastases. She achieved 15 months of progression free survival.
Conclusions: Sunitinib is effective for the treatment of advanced ASPS with lung and brain metastases. The current patient had long-term progression free survival under sunitinib administration.