Abstract
INTRODUCTION: Primary pulmonary myxoid sarcoma (PPMS) is a very rare low-grade sarcoma. It is known to have a characteristic chromosomal translocation at t(2;22)(q33;q12) and a distinctive genetic alteration, Ewing sarcoma breakpoint region 1 (EWSR1):cAMP response element binding protein 1 fusion. Most cases of PPMS reported so far have been found in the bronchi or bronchioles, and there are only a few cases of them arising from the peripheral lung parenchyma. CASE PRESENTATION: A 58-year-old man was referred to our department for diagnosis and treatment because a computed tomography (CT) scan showed a 15mm nodule in the left lung. For diagnosis and treatment, he underwent a video-assisted wedge resection. The tumor protruded from the lung parenchyma and had a very striking appearance. Histological features and immunostaining results were not enough to make the diagnosis. Fluorescence in situ hybridization (FISH) analysis was subsequently performed, which suggested EWSR1 gene rearrangement, leading to the final diagnosis of PPMS. The patient is alive 18 months postoperatively with no evidence of recurrence. CONCLUSIONS: We encountered a rare case of PPMS arising from the peripheral lung parenchyma. In addition, our case was diagnosed as an overlap lesion of PPMS and angiomatoid fibrous histiocytoma. We can expect a good prognosis with surgical resection alone for the treatment of PPMS, but more accumulation of cases is desired for the establishment of an accurate diagnosis and prediction of the disease course.