Simultaneous multifocal sarcomatous degeneration in Paget's disease of bone. A hypothesis.

Multisite pagetic sarcoma was present in three of 18 patients with pagetic sarcomas treated during a 12-year period at two centers. A hypothesis of multifocal origin of the tumor is supported by the sarcoma arising only in pagetic bone, the infrequency of metastases to bone, evidence of multiple sites at presentation, and the rarity of new lesions developing in bone under observation. Survival was shorter with multisite disease than with other pagetic sarcomas.