Pulmonary artery sarcoma: a histologic and follow-up study with emphasis on a subset of low-grade myofibroblastic sarcomas with a good long-term follow-up.

Primary sarcomas of the pulmonary artery are rare, with few series correlating histologic features with follow-up data. We present a series of 43 pulmonary artery sarcomas with primary intraluminal growth, 32 with follow-up information. Symptoms were generally related to shortness of breath and often attributed to recurrent pulmonary embolism. There was no sex predilection. There were 28 pleomorphic-fascicular sarcomas, ranging from relatively differentiated spindle cell myxofibrosarcoma to undifferentiated round-cell sarcoma, often with histologic heterogeneity and overlap. The remaining tumors were 7 osteosarcomas, 4 leiomyosarcomas, 1 rhabdomyosarcoma, and 3 intravascular low-grade myofibroblastic sarcomas. Of the pleomorphic-fascicular sarcomas, 2 demonstrated extensive fibrosis with hyalinization and pleomorphic tumor cells were confined to a luminal rim of neoplastic cells. Histologically, mitotic rate was significantly lower in low-grade myofibroblastic sarcoma than in the other histologic subtypes. Follow-up revealed that 2 of 3 intra-arterial low-grade myofibroblastic sarcomas were cured with no evidence of disease at long-term follow-up. The other tumor subtypes, which represented intermediate and high-grade sarcomas, demonstrated 5 survivors of greater than 3 years, none surviving without disease. The only parameters associated with prolonged survival, other than low-grade myofibroblastic phenotype, was age less than 40 years at onset of symptoms. We conclude that survival beyond 3 years is possible for primary pulmonary artery sarcoma, but cure without evidence of disease is currently possible only for the select subtype of intravascular low-grade myofibroblastic sarcoma.