I was prompted to delve into this topic not because I had a patient with the problem, but because of a MDLink to an article (the first one listed below, subscription required).
The eMedicine article states:
Pyoderma gangrenosum (PG) is an uncommon ulcerative cutaneous condition of uncertain etiology. Pyoderma gangrenosum was first described in 1930. It is associated with systemic diseases in at least 50% of patients who are affected. The diagnosis is made by excluding other causes of similar appearing cutaneous ulcerations, including infection, malignancy, vasculitis, collagen vascular diseases, diabetes, and trauma. Ulcerations of pyoderma gangrenosum may occur after trauma or injury to the skin in 30% of patients; this process is termed pathergy.
The 2 primary variants of pyoderma gangrenosum are the classic ulcerative form, usually observed on the legs, and a more superficial variant known as atypical pyoderma gangrenosum that tends to occur on the hands.
Pyoderma gangrenosum (PG) is not common. It occurs in about 1 person per 100,000 people each year in the United States. Basically, PG is a noninfectious neutrophilic dermatosis.
Patients with PG may have involvement of other organ system, most commonly the heart, the central nervous system, the GI tract, the eyes, the liver, the spleen, bones, and lymph nodes.
It is characterized by the presence of 1 or more ulcerations that are typically violaceous with an undermined border. Diagnosis is clinical and dependent on the exclusion of other causes of cutaneous ulceration. No specific pathologic or laboratory findings exist. Concurrent systemic disease occurs in 50% of affected patients. Commonly associated conditions include inflammatory bowel disease, arthritis, and hematologic malignancy. The remaining cases are considered autoimmune or idiopathic
The 5th reference article is open access. The article is a case presentation of PG localized on the breast (photo credit) in a 51-year-old woman who presented with a large, moderately painful ulceration on her right breast which began 12 days prior to presentation with no history of injury or trauma.
Along with the case presentation, the authors notes that in a literature review only 31 cases of PG had been reported (article published in (January 2010).
In most of these cases the lesions were related to previous surgical interventions, probably as the result of a pathergy phenomenon. The main differential diagnoses were skin and soft tissue infections including necrotizing fasciitis, and malignant neoplasms. Negative initial wound cultures and the relative sparing of nipple/areola complex helped to eliminate these disorders.
PG doesn’t respond to antibiotic therapy or the usual wound care. This is a often the first tipoff. The recommended therapy involves steroids not antibiotics.
Topical therapies include gentle local wound care and dressings, superpotent topical corticosteroids, cromolyn sodium 2% solution, nitrogen mustard, and 5-aminosalicylic acid. The new topical immune modifiers tacrolimus and pimecrolimus may have some benefit in certain patients.
Systemic therapies include corticosteroids, cyclosporine, mycophenolate mofetil, azathioprine, dapsone, tacrolimus, cyclophosphamide, chlorambucil, thalidomide, tumor necrosis factor-alpha (TNF-alpha) inhibitors, and nicotine.
Intravenous therapies include pulsed methylprednisolone, pulsed cyclophosphamide, infliximab, and intravenous immune globulin.
Other therapy includes hyperbaric oxygen.
Surgery should be avoided, if possible, because of the pathergic phenomenon that may occur with surgical manipulation or grafting, resulting in wound enlargement. In some patients, grafting has resulted in the development of pyoderma gangrenosum at the harvest site. In the cases in which surgery is required, the best plan, if possible, is to have the patient on therapy in order to prevent pathergy.
1. Pyoderma gangrenosum of the breast: A diagnosis not to be missed; A. Duval, N. Boissel, J.M. Servant, C. Santini, A. Petit, M.D. Vignon-Pennamen; Journal of Plastic, Reconstructive & Aesthetic Surgery - 20 September 2010 (10.1016/j.bjps.2010.07.022)
2. Pyoderma Gangrenosum; eMedicine article, March 23, 2010; J Mark Jackson, MD, Jeffrey P Callen, MD
3. Pyoderma gangrenosum; Orphanet Encyclopedia, September 2003; Wollina U.
4. Atypical Pyoderma Gangrenosum After Breast Reduction; Karoly Gulyas, FrankW. Kimble; Aesthetic Plastic Surgery Vol 27, No 4, 328-331, DOI: 10.1007/s00266-003-3017-y
5. Pyoderma gangrenosum on the breast: A case presentation and review of the published work; Ayşe Tülin Mansur, Deniz Balaban, Fatih GÖKTAY, Sezen Takmaz, The Journal of Dermatology, Special Issue: Systemic Sclerosis (pages 1-84) Volume 37, Issue 1, pages 107–110, January 2010; DOI: 10.1111/j.1346-8138.2009.00756.x