Gastrointestinal. A preliminary gastrointestinal evaluation included stool culture and tests for clostridium difficile toxin, viral antibodies for cytomegalovirus (CMV), parvovirus, and herpes—all results were negative.
Colonoscopy, however, demonstrated colonic ulcers (mainly of the right colon) with skip pattern associated with polypoid lesions, mild terminal ileitis, and normal-looking left colon and rectum (FIGURE 4). Colonic biopsy showed crypt distortion and abscesses, terminal ileitis, absence of granuloma formation, and negative immunostain for CMV. Colonoscopy findings along with colon biopsy were suggestive of Crohn’s disease.
Conclusions from the lab tests. Blood, urine, and skin lesion cultures remained negative. Urethral and vaginal cultures for gonorrhea, chlamydia, herpes virus, and serum test for syphilis, HIV, and hepatitis B and C were all negative. Biopsy of skin lesions showed dermal mixed inflammatory infiltrate predominantly neutrophilic, and no vasculitis or micropathogens. Absence of micropathogens, vasculitis, vascular thrombosis, and lack of neoplastic cells made infectious, vasculitic, vaso-occlusive and malignant ulcers implausible.
There is no specific laboratory or pathological finding for diagnosis of pyoderma gangrenosum. Diagnosis is based on exclusion of other ulcerative conditions. Negative skin, arthrocentesis, joint fluid and tissue cultures, progressive necrosis of debrided tissue margins (pathergy), and skin biopsy suggested a diagnosis of pyoderma gangrenosum.
Joint lesions were considered to be atypical pyoderma gangrenosum. Investigations to diagnose or exclude a concomitant systemic disorder are required in patients with pyoderma gangrenosum. This patient had Crohn’s disease associated with pyoderma gangrenosum.
FIGURE 4
Colonoscopy findings
