Sclerosing vascular variant of plasma cell granuloma

A single mass in the right lung was found in a 33 year old asymptomatic male by routine chest x-ray examination. In the surgically removed right middle lobe was a well circumscribed but nonencapsulated round tumor (diameter, about 4 cm.) compressing and gradually becoming incorporated into the adjacent pulmonary parenchyma. Histologically the bulk of the tumor consisted of numerous hyalinized blood vessels in a loose mesenchymal background, the latter containing spindle shaped connective tissue cells and an acid mucopolysaccharide stroma. At the margins in the fibrous septa, which divided the tumor into nodules, there was intense lymphoplasmacytic infiltrates forming lymphoid follicles. No epithelial elements were observed around the hyalinized blood vessels. Electron microscopic findings suggest mesenchymal cells, giving rise to endothelial cells of numerous blood vessels and spindle cell connective tissue cells associated with unique lymphoplasmacytic aggregates. The unusual tumor best fits the characteristics of the sclerosing plasma cell granuloma, composed predominantly of sclerosing vascular vessels.