Complex Erdheim-Chester disease associating rectal adenocarcinoma and breast cancer

Erdheim-Chester Disease (ECD) is a rare form of non-Langerhans' cell histiocytosis (non-LCH). It is characterized by the excessive production of histiocytes. We present the case of a 63 year-old Caucasian woman with ECD, with a history of breast cancer (diagnosed in 2006) and rectal cancer (diagnosed in 2013). Most probably, the initial ECD manifestation occurred within the next 5 years after mastectomy in the soft tissues adjacent to the scar. Recently it became manifest in a different localization (meta-diaphysis of long bones), while the other possible sites like the lungs, central nervous system and pituitary gland show minimal involvement with no specific clinical manifestation yet. Shortly after the bone manifestations were detected, she developed an invasive rectal adenocarcinoma. The ECD diagnosis was based on bone scintigraphy, radiography and immunohistochemistry examination.