Pyoderma gangrenosum is a rare dermatosis characterized by rapidly progressive skin ulceration. The etiology of this entity is poorly understood but neutrophil and monocyte dysfunctions (defects in phagocytosis and chemotaxis) have been reported [
1‐
6]. In around half of cases, pyoderma gangrenosum is associated with various underlying specific conditions, most frequently rheumatoid arthritis, inflammatory bowel disease or myeloproliferative disorders. There have been only a few reports on the association of pyoderma gangrenosum with solid malignancies including breast cancer [
7‐
11]. Additionally, a few cases of pyoderma gangrenosum of the breast precipitated by breast surgery were reported [
11‐
13]. The most common location of pyoderma gangrenosum is the legs but the disease may also involve other regions. Differential diagnosis includes Sweet’s syndrome, characterized by similar histologic features, fungal infections and inflammatory diseases of subcutaneous tissue [
2,
4,
6]. The recommended first-line treatment is steroids or other immunosuppressive drugs, such as cyclosporine, azathiopirine, mycophenolate mofetil, cyclolophosfamide, chlorambucil or thalidomide [
14]. Surgery is contraindicated due to pathergy, which is characterized by the development of new lesions at the site of even minor trauma [
13]. Importantly, pyoderma gangrenosum management should be accompanied by treatment of the underlying disease, although surgery or radiotherapy may induce rapid development of ulceration at the site of therapeutic intervention [
7,
11‐
13].
In our patient, pyoderma gangrenosum was most likely induced by progressing breast cancer. The causative role of the neoplastic process was partly confirmed by the healing of the skin ulceration only following effective endocrine cancer therapy, whereas earlier attempts with corticosteroids were unsuccessful. The lack of improvement with corticosteroids has been atypical, as this therapy usually induces dramatic response within the first two weeks [
14]. Another interesting feature of this case was the recurrent nature of pyoderma gangrenosum, with its first appearance 30 years earlier, during an exacerbation of rheumatoid arthritis. Thus, probably this entity may be reactivated by various causes within several years.