Pseudotumoural fibrous dysplasia of the maxilla: radiological studies and computed tomography contribution.

Clinical, radiological, and histological problems arise relating to fibrous dysplasia of the maxilla. Clinically, 11 of our 39 cases developed so rapidly that the lesions were suspected of being malignant. The histological diagnosis may be very difficult, since any tumoural, reactive, or healing process may simulate fibrous dysplasia. As a general rule, the diagnosis is established most easily by the radiological examination. The radiologist's responsibility is important, as mistakes may have serious consequences. We report four pseudotumoural forms of maxillary sinus fibrous dysplasia. All were characterised clinically by rapid evolution, radiologically by opacity of the sinus with apparent destruction of its wall, and histologically by difficulty in establishing the diagnosis. In two cases indeed, the initial histological interpretation was an osteogenic sarcoma. Due to its excellent densitometric resolution, computed tomography provides an invaluable contribution by displaying the fibrous wall of an intact or even thickened maxillary sinus when conventional radiology has suggested a destructive process. In difficult cases of maxillary fibrous dysplasia, computed tomography should be used as a supplementary investigation to establish the correct diagnosis.