Posttraumatic fibro-osseous lesion of rib.

Eleven cases are described of an unusual, benign, fibro-osseous lesion of rib previously reported under a variety of designations, including painless fibro-osseous lesion resembling osteoid osteoma, symmetrical fibro-osseous dysplasia, focal Erdheim-Chester disease, and fibro-osseous pseudotumor. All patients were adults, most of whom were asymptomatic, the lesion discovered by bone scans done to rule out metastatic disease. A single rib was involved in eight patients and multiple ribs in three. A roentgenographic abnormality was apparent in only five patients. Histologically, all lesions showed a bland fibrous stroma in which resided an anastomosing network of bone trabeculae, having a zonal pattern of maturation from metaplastic woven to mature lamellar bone, with or without an associated xanthomatous component. Seven patients had a history of previous trauma, three with fractured ribs. Considering the relative infrequency of solitary rib lesions attributable to metastatic disease, it is proposed that in most cases there is no need for a diagnostic rib resection for these incidentally discovered, posttraumatic reparative lesions.