Sclerosing orbital pseudotumor: a unique clinicopathologic entity.

A case of orbital pseudotumor is presented that histologically showed dense fibrosis invading bone and adjacent sinuses, and failed to respond to either steroids or radiation therapy. "Orbital pseudotumor" remains a sobriquet for a variety of clinical and histopathologic entities including a monomorphous lymphocytic benign or malignant neoplasm; a polymorphous reactive inflammatory lesion; and a densely fibrosing sclerotic variant that appears to behave more aggressively, often locally invades adjacent structures, and may be related to a multifocal fibrosclerosis that also includes retroperitoneal fibrosis, Riedel's sclerosing thyroiditis, mediastinal fibrosis, and sclerosing cholangitis. This "sclerosing orbital pseudotumor" is felt to represent a unique clinicopathologic entity, and an approach to its treatment is described.