RESUMEN
The histiocytosis X is a tumoral affection related to the proliferation of a highly differentiated cell which reaches the reticulohistiocytary system. The radiology represents on top of the clinic and the histology, the central pillar of this diagnostic tripod. This retrospective study is about 14 files of patients collected in different departments of UHC Ibn Rochd between 1976 and 1988. In the 14 observations, the diagnosis has been confirmed by an anatomopathologic examination. The disease supervenes with predominance at the young age (9 cases 11 years). The reach of the bone is very frequent (9/14 cases) and often multiple (7/9 cases), the preferential localizations are at the craniofacial level (50%), at the level of flat bones, the girdles (25%), the femur and the tibia (25%). The radiologic aspect is an osteolysis in the shape of lacunae with rounded and outlines suited with "take-piece", sometimes polycyclic in the card of geography. This osteolysis has sometimes a quite characterized aspect of the disease especially at the level of the cranium, the maxillomandibular massive, the supracotyloid region and the rachis. The reach of the lun during the histiocytosis X is relatively frequent (4/14 cases). It is often about an interstitial pneumopathy that is sometimes complicated of pneumothorax. The standard radiologic examinations of the osseous Skeleton help in making the diagnosis, permitting the complete physical examination of the extension and the supervision of the disease. The scintigraphy is less reliable and the scanner is not specific. However, the scanner explores better the base of the Skull and certain viscers which the reach can make revise the prognosis.