Nonepiphyseal giant cell tumor of the long bones. Clinical, radiologic, and pathologic study.

Background: Giant cell tumors (GCT) usually involve the epiphyses of long bones and only rarely involve the metaphysis or diaphysis without epiphyseal extension.

Methods: This report presents the clinical and pathologic features of 14 patients with metaphyseal and diaphyseal GCT. Of these tumors, 10 were metaphyseal; 2, metadiaphyseal; and 2, diaphyseal.

Results: The sites of involvement included the proximal tibia in six patients, distal radius in three, proximal fibula in one, distal fibula in one, distal ulna in one, proximal humerus in one, and distal femur in one. Radiographically, the tumors were lucent, and the majority were sharply marginated without sclerosis. By contrast with conventional epiphyseal GCT, which generally appear in the mature skeleton, a large proportion (50%) of the GCT in this series were in patients who had open epiphyseal growth plates. Despite the unusual clinical presentation, the behavior of metaphyseal and diaphyseal GCT was similar to that of the typical epiphyseal GCT. There was a 43% recurrence rate after curettage in this series.

Conclusions: It is important to distinguish this subset of GCT from other giant cell-rich lesions more common in these sites, including aneurysmal bone cyst, osteosarcoma, and nonossifying fibroma.