An unusual case of bilateral primary pleural angiosarcoma with an immunophenotype of lymphangioendothelial lineage is described. Pleural angiosarcoma is a highly malignant neoplasm for which there is currently no standard of care. A comprehensive immunophenotypic characterization established a lymphangioendothelial lineage. A morphoproteomic analysis was also performed to identify the proteins and corresponding molecular pathways activated in the patient's tumor. The information derived from the morphoproteomic studies provides insight into the biology of the tumor and may be useful in formulating therapeutic alternatives.