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Poster: 1Pyoderma Gangrenosum in Revision Total Hip Arthroplasty: Clinical andHistopathological Findings.- - ,Ariella Zbar - UVIC / UBC Island Medical School - Victoria, CanadaJames Mathers - UVIC/UBC Island Medical School - Victoria, CanadaDouglas Sawyer - UVIC-UBC Island Medical School - Victoria, Canada* - - ,Introduction: Pyoderma gangrenosum (PG) is a medically treatable neutrophilic ulcerativedermatosis which may occur in surgical or traumatic wounds. This poster report describes theclinical and histopathological findings associated with PG in revision total hip arthroplasty(THA).Methods: A 76 year-old male underwent revision THA and required warfarin for paroxysmalatrial fibrillation. Postoperatively, he developed wound drainage, skin blistering with bullae anda necrotic purulent appearance, and an elevated INR(6.8). He returned to the OR for presumedinfection (or possible warfarin induced skin necrosis), underwent irrigation and debridement –the fascia was intact and cultures were negative. A well-demarcated atypical ulcer, with anirregularly bordered area of redness was noted around the wound, which was biopsied inmultiple locations. At 3-years following revision, the hip is functioning normally and the ulcerand skin have remodelled and the patient is asymptomatic (Fig 4)Results: The histology of the biopsy demonstrates the typical findings associated with PGincluding (Fig 1,2)ulceration with epithelial undermining. The ulcer is covered byfibrinopurulent exudate along with the presence of a dense dermal neutrophilic infiltrate. Highermagnification (Fig 3) demonstrates lysis of collagen within the ulcer. Warfarin induced skinnecrosis would show vascular thrombi with initial bland necrosis, differentiating it from PG.Discussion: PG is a clinically distinctive, but non specific, necrotic ulcer that may occur at asurgical site and may mimic infection or warfarin-induced skin necrosis. PG is previouslyunreported in revision THA. Confirmation of the diagnosis requires clinical-pathologiccorrelation and exclusion of infection by appropriate microbiological studies. This is importantas the primary management is medical and not surgical.Summary: Pyoderma Gangrenosum is a necrotic ulcer which may mimic surgical infection orwarfarin induced skin necrosis. PG is previously unreported in revision THA, and is treatable.Figure legend:Figure 1: The biopsy shows (a) ulceration with epithelial undermining. The ulcer is covered byfibrinopurulent exudates along with the presence of a dermal neutrophilic abscess.(Haematoxylin-Eosin, 40x)Figure 2: Epithelial undermining shown in a higher power view. (Haematoxylin-Eosin, 100x)Figure 3: Higher magnification demonstrates lysis of collagen within the ulcer. (Haematoxylin-Eosin, 200x)Figure 4: Clinical photograph of the healed ulcer over the right hip at 36 months postop.file:///E|/ISTA2010-Abstracts.htm[12/7/2011 3:15:47 PM]