Abstract
Erdheim Chester disease is a rare disease characterized by abnormal proliferation of histiocytes. The most commonly affected site is the long bones, while involvement of the breasts is very rare. In patients with breast involvement, a unilateral breast mass is the most common presentation. We present a unique case of Erdheim Chester Disease initially presenting as diffuse, bilateral breast dimpling and erythema in a 45-year-old female. Clinically, the presentation mimicked inflammatory breast carcinoma with diffuse breast dimpling, erythema, and associated breast masses, and differing in that both breasts were involved. Diagnostic breast imaging and histopathology led to a comprehensive multidisciplinary approach to diagnosis and management of Erdheim Chester Disease. Although rare, Erdheim Chester Disease should be considered in the differential diagnosis of atypical breast lesions.