Pyoderma Gangrenosum of the Breast: A Diagnostic Challenge.

Introduction: Pyoderma gangrenosum (PG) is a rare, noninfectious neutrophilic dermatosis usually located in the legs. PG of the breast is infrequent and may be a diagnostic challenge. Our objective was to review our patients with breast PG in order to analyse their clinical features. Methods: Patients diagnosed with PG involving the breast in Bellvitge University Hospital (Barcelona, Spain) between 2000 and 2023 were included in the study. Medical charts were retrospectively reviewed to obtain clinical data. Results: Ten patients were diagnosed with breast PG (10 women aged between 30 and 63 years, median 49.5). Evolution time at diagnosis ranged between 4 days and 7 months. In all cases, PG lesions were painful. All patients presented ulcerated lesions. In 2 cases, nodular abscess-like lesions and cribriform scars were also observed. The nipple was involved in 4 cases. Two patients had underlying diseases recognized as frequently associated with PG (ulcerative colitis and rheumatoid arthritis). Seven patients had a previous breast surgery that was considered related to PG (removal of breast carcinoma with breast reconstruction in 6 cases and breast reduction in one). The diagnosis of postsurgical breast PG was delayed in 6 patients by between 3 and 7 months. One patent developed radiation therapy induced pathergy after healing of postsurgical PG. Conclusion: The most common triggering factor for breast PG in our study was reconstruction following surgery for breast carcinoma. Medical professionals who treat breast diseases should be aware of this disease in order to lessen diagnostic delay.