Intimal sarcoma of the pulmonary trunk showing broad intimal extension and focal chondrosarcomatous differentiation: an autopsy case

We report an autopsy case of intimal sarcoma arising in the pulmonary artery with focal chondrosarcomatous differentiation. A 77-year-old woman presented with a thrombosis-like mass in the pulmonary trunk and underwent endarterectomy. Macroscopically, solid and myxomatous tumor expanded to the pulmonary valve and bilateral main pulmonary arteries. Microscopically, the tumor comprised atypical spindle cells proliferating in a fascicular fashion, as well as occasional bizarre multinucleated cells, within a myxomatous stroma. Less than 5% of the tumor cells showed chondrosarcomatous features. Immunohistochemically, tumor cells were diffusely positive for vimentin and partially positive for cytokeratin AE1/AE3, α-smooth muscle actin, and desmin. Electron microscopic analysis failed to reveal specific somatic differentiation of tumor cells. The patient died 2 days after the surgery because of uncontrollable heart failure. Upon autopsy, residual tumor cells were observed only in the left upper intrapulmonary portion of the pulmonary artery. Although the diagnosis of intimal sarcoma can be challenging, earlier histological confirmation of the tumor would lead to appropriate surgical treatment and improved outcomes.