Langerhans cell histiocytosis: another cause of a fluid-fluid level within an appendicular bony lesion.

We report a case of Langerhans cell histiocytosis (LCH) occurring in the pelvis of a 2-year 11-month-old female with fluid-fluid level seen on MRI. Aspiration of the fluid during biopsy showed it to be blood with a few inflammatory cells and eosinophils. Tissue obtained during the biopsy confirmed the diagnosis to be LCH.

Erdheim-Chester disease with rare radiological features in a 14-year old girl with pre-B Acute Lymphocytic Leukemia and Diabetes Mellitus.

We report a case of a 14 year-old girl with Diabetes Mellitus who was in remission with pre-B cell Acute Lymphoblastic Leukemia and subsequently diagnosed with Erdheim-Chester disease. Erdheim-Chester disease is a non-Langerhans cell histiocytosis and is very rare in children. In addition, the radiological features of the lesions are atypical and have not been reported in children.