Erdheim-Chester Disease Presenting as Bilateral Facial Masses

Erdheim-Chester disease (ECD) is a rare form of non-Langerhans cell histiocytosis with unknown etiology. It is recently recognized to be neoplastic with genetic mutations affecting the mitogen-activating protein kinase (MAPK) pathway. We here present a case of a 49-year-old female who initially presented in 2012 with bilateral facial masses to a tertiary care center. These were removed but later recurred over a period of ten years. She then presented with xanthelasmas, bone lesions, secondary infertility due to hypothalamic hypogonadism, diabetes insipidus, and Hashimoto’s hypothyroidism. The facial masses were biopsied, and they showed classic morphological features in the form of diffuse infiltration by foamy histiocytes, with scattered Touton type of giant cells, patchy lymphocytic infiltrates, and dense fibrosis. The presented ECD case is particularly interesting due to the recurrent bilateral facial masses. To the best of our knowledge, this is the first documented case in Oman. The patient is stable and is being followed up in the clinic. Keywords: Erdheim-Chester disease, Langerhans cell histiocytosis.