Pyoderma gangrenosum of the breast: a rare but significant cause of breast ulceration

Pyoderma gangrenosum (PG) is a rare dermatological condition with incidence 3–10 per million population1-4 characterized by rapidly progressive ulceration with raised irregular erythematous borders3, 5 belonging to a spectrum of neutrophilic dermatoses.2, 3, 5-8 Aetiology remains unknown, however, 70% of cases co-exist with underlying autoimmune conditions.1, 2, 4-6, 8 There have been 123 case reports globally of PG of the breast since 1997. Of these, only seven cases (5.7%) were de novo in isolation from systemic disease or post-surgery. PG remains a diagnosis of exclusion and poses a diagnostic challenge with features mimicking necrotizing skin and soft tissue infection.1-8 We report a 48-year-old female with a rare case of PG of the breast. She presented with a necrotic skin lesion of the breast increasing in size despite treatment with oral antibiotics. Medical history included type 2 diabetes mellitus, previous gastric bypass and active smoking. On examination, there was a necrotic lesion in the upper outer quadrant of the right breast sparing the nipple areolar complex, white cell count 15, neutrophils 8, and CRP 11. She was commenced on antibiotics and underwent surgical debridement. Despite extensive skin necrosis, underlying glandular tissue appeared normal. There was no growth on tissue culture and histopathology revealed neutrophilic inflammation and tissue necrosis. She was discharged home post-operatively without further antibiotics. The wound was reviewed 1 and 2 weeks post-operatively, during which time there was progressive necrosis and erythema (Fig. 1a). She was haemodynamically normal, afebrile with normal inflammatory markers. She was admitted for repeat debridement and antibiotics. Debridement revealed extensive skin necrosis but normal glandular tissue (Fig. 1b), a punch biopsy was performed at 12 o'clock away from the wound for culture and histopathology. The wound deteriorated post-operatively with progressive necrosis, development of violaceous wound borders and necrosis at the biopsy site day 1 and 2 post-operatively (Fig. 1c). Infectious diseases, plastic surgery and dermatology teams were consulted and a diagnosis of PG was suspected. The patient was treated with oral and topical corticosteroids and wound dressings. There was marked improvement with granulation of the wound within 72 h. Antibiotics were ceased and the patient was discharged 5 days after commencement of steroids. Screening for malignancy, inflammatory bowel disease and autoimmune disease was negative. The patient was reviewed weekly for four weeks post-discharge, steroids are being weaned and the wound is nearly completely healed (Fig. 1d). Rapidly progressive ulceration in a systemically well patient with normal inflammatory markers, negative tissue cultures, sparing of nipple areolar complex, and progression despite antimicrobials and wound debridement should raise clinical suspicion of PG.1, 2, 5, 8 Crucially, as demonstrated in our case, suspicion should remain in lieu of preceding surgery or systemic disease. Consideration of PG is imperative as deleterious surgical debridement will induce pathergy and increase patient morbidity.1-6, 8 Management principles include blood and tissue culture to exclude infection, trial of antimicrobial coverage, involvement of multidisciplinary teams, avoidance of unnecessary surgical intervention and rapid commencement of systemic corticosteroids.1-7 EE and KG conceived the presented idea and were responsible for manuscript preparation. LT supervised the proceedings of this work and provided surgical expertise, and was the primary consultant on the presented case. All authors reviewed the article and approved the final version of the manuscript.