Giant-cell reaction in the small tubular bones. A light- and electron-microscopic study.

Light- and electron-microscopic investigations were performed in a case of cystic soap-bubble-like expansion of the shaft region of the second metatarsal bone. Morphologically, strongly cellular tissue with a closely packed net of osteoid trabeculae containing osteoblasts and a whorl-shaped spindle cell stroma with fibroblasts, fibrocytes, and irregularly scattered multinucleated giant cells of the osteoclast type were observed. After clinical and morphological exclusion of osteosarcoma, enchondroma, non-ossifying fibroma, osteoblastoma, osteoclastoma, and bone cysts the final diagnosis was giant-cell reaction of small tubular bone with unusual marked osteoid formation. As recurrences are possible, block resection appears more appropriate than curettage.