Erdheim-Chester Disease of the Breast Without Systemic Involvement
Erdheim-Chester disease is a rare non–Langerhans cell histiocytosis, characterized by infiltration of tissues by foamy non–Langerhans cell histiocytes associated with Touton-type giant cells and mixed lymphoid infiltrates. There are fewer than 700 cases reported in the world and only 7 cases with solely breast involvement. We report another 4 cases. Four additional cases of isolated breast involvement in whom the diagnosis was made upon review of the biopsies.
A diffuse infiltration by epithelioid cells with abundant foamy cytoplasm, multinucleated cells with the appearance of Touton-type giant cells, and patchy mature lymphoid infiltrate were found. On immunohistochemical staining, the cells were positive for CD68 and negative for CD1a, S-100, and immunoglobulin G4 (IgG4). These findings were consistent with Erdheim-Chester disease.