Malignant histiocytosis (MH) is a disease which clinically and histologically resembles non-Hodgkin lymphoma. Tumoural cells appear to be derived from histiomonocytes. Clinical signs commonly include: high fever, sudden onset of extreme fatigue, diffuse painful polyadenopathies and infiltrated cutaneous nodules. This study involved the radiological findings of 23 pediatric cases of MH. Thoracic involvement is very frequent (69%) and most often involves mediastinal lymph nodes. Interstitial (34%) and pleural (38%) lesions are often associated. Nine of 21 (42%) lymphographies showed pathologic changes, the most frequent pattern in retroperitoneal nodes was multilacunar and nodes were moderately enlarged. Some isolated lymph nodes were normal. Bone lesions were rare and were either lytic or sclerotic.