Primary pulmonary myxoid sarcoma with detected EWSR1 gene translocation: a case report

Primary pulmonary myxoid sarcoma (PPMS) is an exceedingly rare low-grade malignant sarcoma characterized by the presence of EWSR1 rearrangement and EWSR1::CREB1 fusion, which serve as critical diagnostic markers. Due to its nonspecific symptoms, PPMS is often detected incidentally, complicating its differentiation from other pulmonary neoplasms.

We report a case of a 52-year-old female patient who was admitted in May 2024 after a nodule was incidentally found in the right middle lobe during a routine health examination. Imaging studies revealed a solid nodule with mildly increased radiotracer uptake. The patient declined a biopsy and subsequently underwent uniportal video-assisted thoracoscopic surgery (UVATS) for right middle lobectomy. Intraoperative findings indicated a spherical nodule with significant adherence to the middle lobe vein. The frozen section analysis suggested a likely benign lesion, leading to the omission of lymph node dissection. Postoperative pathological examination confirmed the diagnosis of PPMS with EWSR1::CREB1 fusion, supported by immunohistochemical and fluorescence in situ hybridization analyses. The patient recovered uneventfully, with no abnormalities observed at the six-month follow-up.

PPMS is an extremely rare low-grade sarcoma with significant diagnostic implications due to its genetic characteristics. Surgical resection remains the primary treatment modality, though the potential for local recurrence or metastasis necessitates ongoing monitoring and further research to establish standardized treatment protocols and understand its biological behavior.