Metastatic Retroperitoneal Leiomyosarcoma: Case Report

Introduction: Leiomyosarcomas (LMS) are rare malignant neoplasms originating in smooth muscle, more common in women in their fifth and sixth decades of life. Inherent characteristics of the retroperitoneum allow LMS in this location to reach substantial proportions and present symptoms only in more advanced stages. Case report: A 37-year-old woman sought medical attention in July 2020 due to the growth of a painful, fixed mass in the left hemiabdomen that appeared six months earlier. The patient denied urinary or gastrointestinal alterations but reported an 8 kg weight loss in the last month. Computed tomography identified a lobulated, heterogeneous formation in the left flank measuring 8.5 cm, along with hepatic and pulmonary nodules. Subsequently, surgical resection of the lesion, nephroureterectomy, and hepatic biopsy were performed, confirming the diagnosis of LMS through anatomopathological and immunohistochemical analysis. After unsuccessful adjuvant chemotherapy, she progressed to multiple metastases and is currently undergoing palliative treatment. Conclusion: Detecting and diagnosing retroperitoneal LMS are challenging. Awareness of their aggressiveness, especially in young patients, is crucial to ensure personalized and early interventions, thereby improving the prognosis.