Pyoderma gangrenosum after abdominal surgery—a rare but none the less necessary differential diagnosis

Abstract

Dear Editor: Pyoderma gangrenosum (PG) is part of the spectrum of the neutrophilic dermatoses, a group of inflammatory disorders of unknown aetiology that share a tendency towards pathergy and the presence of noninfectious neutrophilic infiltrates, mainly in the skin. In 40% to 50% of the cases, the formation of PG can be worsened by a nonspecific external stimulus such as a trauma or a surgery. This phenomenon, called pathergy, conduces to avoid any surgical excision of the lesion. However, the diagnosis is often omitted, and the rapid evolution of the cutaneous necrosis forces the surgeon to perform a surgical debridement of the wound as one of the main differential diagnoses is a necrotizing fasciitis that requires a fast surgical reaction. Then, it often causes an exacerbation of the lesion, and it can have disastrous consequences. Unlike PG, which may appear spontaneously or as a result of the pathergy phenomenon, postoperative PG (PPG) is clearly related to previous surgery. PPG, also known as postoperative progressive gangrene of Cullen, is a rare and rapidly developing complication of surgical procedures. Since the first description by Cullen in 1924, nearly 100 cases of PPG developing on surgical wounds have been reported. The diagnosis of PPG is based on clinical features and always requires exclusion of other conditions, as misdiagnosis exposes patients to risks associated with inappropriate treatment. Sequencing of 16S ribosomal (r)RNA is an accurate method for microbial detection, and identification to exclude an infectious origin in cases where cultures do not grow microorganisms and antibiotics have been previously given to patients. Nevertheless, histopathology of the skin is the most common investigation to confirm the diagnosis of PG. Here, we report a case of an abdominal PPG that occurred after laparoscopic sigmoidectomy. A 39-yearold patient was transferred to our hospital with a progressive ulceration at the lower abdomen 3 weeks after a laparoscopic sigmoid resection due to diverticulosis. Shortly after the initial surgical procedure, the patient emerged a wound infection at the site of the resection area of the sigmoid in the right lower abdomen. The initial bacterial culture showed an infection with Staphylococcus aureus that was sensitive for standard antibiotics. In the following, the patient was treated with piperacilline/sulbactam, but the wound situation didn’t improve. After surgical wound debridement and ongoing treatment with antibiotics but progressive phlegmon, the patient was transferred to our hospital due to a suspected infection with anaerobic bacteria and necrotizing fasciitis. The initial serum infection parameters showed a high leucocytosis of 19.76 G/l (standard value 6.0–9.0 G/l) and a C-reactive protein (CRP) of 13.6 mg/dl (standard value <0.5 mg/dl) with additional temperature of 37.9°C. The initial applied antibiotic treatment was continued in case of the initial wound culture and positive S. aureus and the fact that the wound infection started after the sigmoid resection. The local inflammatory signs progressed in the following 2 days up to a leucocytosis of 43.63 G/l and a No financial support.