RESUMEN
BACKGROUND: Soft tissue sarcomas (STS) account for approximately 1% of adult malignancies, with 50 to 60% occurring in the extremities. Liposarcoma is the most common type of STS and represent about 20% of total adult sarcomas. There are rare syndromes associated with increased risk of developing STS. Further, chemical compounds such as chlorinated phenols and a few chemotherapeutic drugs have been linked to STS, along with ionizing radiation. Nevertheless, the etiology is uncertain for most of these lesions. CASE REPORT: This report details 2 cases of metachronous bilateral STS of the lower extremities. The first of these presented as a local recurrence of a previously resected right thigh liposarcoma and a new liposarcoma in the left thigh. As mentioned above, among the different subtypes of STS, liposarcoma has the highest tendency for multifocality. The second patient had multifocal metachronous leiomyosarcoma with lung metastases occurring simultaneously with the second presentation. Leiomyosarcoma is another subtype reported to present with multifocal disease. CONCLUSIONS: Despite the rarity of bilateral lesions, their occurrence should not be overlooked in the initial diagnosis and follow-up of the initially detected tumor. Early detection can affect patient survival because their presence predicts unfavorable outcomes.