A 60-year-old woman with a high-grade myxofibrosarcoma of her left forearm, submitted to surgical excision and postoperative radiotherapy, presented to the emergency department, after 3 years, with a 2-months history of progressive asthenia and shortness of breath. On physical examination the patient had a good general condition, was acyanotic and with eupneic breathing. Cardiovascular assessment revealed a regular heartbeat with normal heart sounds, without murmurs. The peripheral oxygen saturation on room air was 94% and the vesicular murmur was absent in the entire right hemithorax. Chest computed tomography (CT) revealed a large and heterogeneous mass on the right hemithorax, measuring 13 × 9.4 × 16.4 cm, with a medium-volume pleural effusion ipsilateral (Panel 1A and B). A transthoracic biopsy was performed and the histological examination was compatible with metastasis of myxofibrosarcoma.

Following a multidisciplinary team discussion, the patient started systemic treatment with chemotherapy (doxorubicin and ifosfamide, every 3 weeks, intravenously) and was referred to the palliative care team. After 2 cycles, clinical improvement was evident, associated with a slight radiological response on CT (thoracic metastasis measuring, at this time, 12.5 x 9 x 15.5 cm). However, the patient died after these 2 cycles, due to SARS-CoV-2 infection.

Myxofibrosarcoma exhibits a high local failure rate (up to 79%), probably due to the infiltrative growth pattern. However, in some cases, distant spread can occur. The lung is the main site for sarcomatous metastasis, with multiples and well-defined nodules being one of the most common dissemination patterns. However, here we describe a case of a big, unique and bizarre sarcomatous thoracic metastasis.