Pyoderma gangrenosum with a contiguous erosion of the distal ulna.

Background: Pyoderma gangrenosum (PG) has been described in association with sterile neutrophilic infiltration of several organ systems, including the skeleton. The most frequent cause of bony disease in PG has been chronic, recurrent, multifocal osteomyelitis, a sterile inflammatory disease of children and young adults mimicking infectious osteomyelitis. Bony erosions have been only rarely described in direct contiguity to a PG ulcer.

Objective: We report a 53-year-old woman with recurrent PG who developed an erosion of the distal ulna adjacent to a PG ulcer. The patient responded to high-dose prednisone, and a repeat radiograph of the wrist four months later was normal.

Conclusion: This case demonstrates another example of cortical osteolysis directly adjacent to a PG ulcer in which the bony changes may be neutrophil-induced.