Rapidly Progressive High-Grade Leiomyosarcoma in an Elderly Patient.

An 84-year-old female with a history of hypertension, diabetes, and hypothyroidism initially presented in November 2023, with a rapidly enlarging (19.5 cm) left proximal thigh mass. Biopsy diagnosed high-grade leiomyosarcoma, which doubled in size within two weeks, confirming aggressive biology. In January 2024, the patient, who had been ambulating independently one year prior to her diagnosis, underwent radical resection and femoral neurolysis, and initiated radiotherapy, without receiving neoadjuvant chemotherapy due to cachexia. Three months postoperatively, in April 2024, the patient presented with acute respiratory distress, requiring 4L oxygen, and bilateral lower extremity edema. Imaging revealed numerous bilateral pulmonary metastases and an acute pulmonary embolism in the right inferior segment branch. She was admitted with decompensated heart failure, an ejection fraction of 30-45%, and extensive metastatic leiomyosarcoma. Despite anticoagulation, her status rapidly declined.  This case highlights the challenges of rapidly progressive sarcomas characterized by fulminant growth and early metastatic spread. Earlier treatment with neoadjuvant chemotherapy prior to surgery may have improved outcomes but was precluded by the patient's frailty. After a multidisciplinary discussion, the decision was made to transition to hospice care. This case also underscores the potential for rapid clinical deterioration with metastatic leiomyosarcoma. It highlights the challenges of managing complications from aggressive malignancies, especially in frail patients, where treatment-related toxicities may outweigh the benefits. Careful patient selection for cancer-directed therapies via multidisciplinary input is imperative.