(18)F-FDG positron emission tomography/computed tomography and (99m)Tc-MDP skeletal scintigraphy in a case of Erdheim-Chester disease.

A 24 years old man came at our attention for polydipsia with nocturnal and diurnal polyuria, anorexia, febrile episodes (38° C), and arthromyalgia especially in the knees. Physical examination showed bilateral periorbital xanthelasma. Blood exams showed increase of plasma osmolarity, haematocrit, sodium and urea and decrease of potassium. Urine exams showed just decreased urine specific gravity, (1.001; normal range: 1.010-1.030) suggestive for central diabetes insipidus. In conclusion, the 18F-FDG PET/CT scan and the 99mTc-MDP scan depicted many of the most relevant lesions of ECD for the initial assessment of ECD in our patient.