FDG PET images in a patient with Erdheim-Chester disease.

Erdheim-Chester disease is an uncommon non-Langerhans-cell histiocytosis, due to excessive production of histiocytes deposited in various organs and tissues in the human body. FDG PET was performed in a 68-year-old man with documented active Erdheim-Chester disease to evaluate the extent of the disease. The patient was previously treated with high-dose subcutaneous Interferon α2b, 1,000,000 units 3 times a week, but treatment was interrupted approximately 5 weeks before evaluation at the National Institutes of Health because of adverse effects of the medication. FDG PET/CT showed lesions were imaged in brain, heart, mediastinum, abdomen, and skeleton.