Giant cells in pyoderma gangrenosum

It has been claimed that pyoderma gangrenosum (PG) lesions may contain gran ulomatous foci when associated with Crohn's disease. To test this assertion , we obtained clinical histories and archived cutaneous biopsies from 34 PG patients. Thirteen of these patients had inflammatory bowel disease (IBD). Immunostaining with PGM1, a macrophage marker, revealed well-formed giant cells with three or more nuclei in biopsies from 6 of 13 patients with IBD. Five of the 6 biopsies came from patients with Crohn's disease and one fro m a patient with ulcerative colitis. Two were peristomal. In the 21 patient s who had PG without IBD, no giant cells were seen. Thus, PGM1 + histiocyti c giant cells within a PG lesion may be indicative of associated IBD (p=0.0 06), particularly Crohn's disease.