Osteoporosis Circumscripta

Skull x-ray films were taken after this 62-year-old nursing home resident fell and hit his head. The radiographs revealed only a sharply demarcated radiolucent area, mainly over the right parietal bone (A). Osteoporosis circumscripta was diagnosed.

This disorder represents the initial or destructive phase of Paget's disease of bone, or osteitis deformans. Typically, this disorder is asymptomatic and is often discovered from x-ray or laboratory studies performed for other conditions.

Paget's disease, a focal inflammatory condition, is characterized by a three-phase aberrant pattern of bone resorption and formation.¹ The large osteoclasts with multiple nuclei that develop in the first phase are best seen in the skull (B). This process usually begins in the frontal or occipital area, spreads across suture lines, and slowly encompasses most of the calvaria.

The second, or osteoblastic, phase of the disease is marked by both bone destruction and chaotic repair efforts, which usually are most evident in the pelvis and long bones (C). The pelvis and clavicles best reveal the mosaic pattern of dense bone that typifies the quiescent or sclerotic third phase of Paget's disease (D).

Most patients with early Paget's have localized disease and are asymptomatic. They require no treatment.

REFERENCE:1. Wallach S. Identifying and controlling Paget's disease. J Musculoskel Med. 1997;14(6):66-82.