Pyoderma gangrenosum may mimic breast cancer in a rare differential diagnosis: A case report

Pyoderma gangrenosum (PG) is a rare skin disease characterized by neutrophilic inflammation, often associated with systemic pathologies. Although this condition generally affects other areas of the body, it can occasionally manifest in the breast, where it can mimic neoplastic or infectious lesions. A clinical case illustrates this rare presentation: a 68-year-old Moroccan patient, initially referred for suspected breast cancer, presented with painful, rapidly progressing ulcerative-necrotic lesions on the breast with purplish edges. These lesions were accompanied by localized skin involvement on the leg. Histological examination of the breast lesions revealed a neutrophilic infiltrate, suggesting an inflammatory origin. In addition, worsening of symptoms was observed after a breast biopsy, suggesting a pathergy reaction. Further investigations led to a diagnosis of rheumatoid arthritis (RA) associated with systemic lupus erythematosus (SLE), while infectious and tumor assessments were negative. The definitive diagnosis of Pyoderma gangrenosum was confirmed. Combined treatment including corticosteroids, immunosuppressants, and local care was implemented. This case highlights the importance of an accurate differential diagnosis when a breast ulcer is observed, in order to avoid diagnostic errors, prevent inappropriate treatments, and reduce the risk of serious functional and aesthetic consequences for the patient.