Osteolytic Paget's disease. Recognition and risks of biopsy.

The cases of five patients with the predominantly osteolytic form of Paget's disease affecting weight-bearing long bones are described. The diagnosis was not recognized initially in three. In two of them a biopsy was performed, and one subsequently had a fracture through the biopsy site more than a year later. In all five, calcitonin treatment was effective in restoring the bone architecture toward normal as determined radiographically. Relapse occurred in two patients shortly after the cessation of calcitonin treatment and in a third despite continued treatment. The flame-shaped resorption from of the osteolytic component of Paget's disease has a pathognomonic appearance radiographically. Radionuclide bone-scanning can help in establishing the diagnosis. Diagnostic biopsy of such an area, particularly in a weight-bearing long bone, is unnecessary and should be avoided because of the increased risk of fracture.