["Empty cysts" of the jaws]

The extensive use of orthopantomography contributed to the occasional discovery of the so called empty cysts (EC) also defined as traumatic or hemorrhagic, which are benign mainly asymptomatic lesions. There are different opinions on empty cysts (even on the proper term to define them) particularly regarding their epidemiology, etiopathology, and clinical and radiological aspect. The purpose of this study is to compare the literature and personal experience and to underline the peculiar aspects not only from a semantic point of view, but also from a more elaborate perspective.

Forty-five osteolytic lesions, which can be considered as empty cysts, taken out of a group of 30,000 patients in a period of 5 years have been examined retrospectively. Radiologic documentation included: orthopantomography, occlusal radiographs, intraoral periapical radiographs, intraoral tube panoramic radiographs and TC in 4 cases. Several parameters among which: trauma, symptoms, location, dimension and the radiological aspect of the lesion were taken into account.

The authors concluded: trauma in 4 cases, location of 44 out of 45 empty cysts in the mandible, 67% of which distal to canines; displacement of adjacent teeth in four cases, without root resorbtion. The major axis of empty cysts varied from a minimum of 18 to a maximum of 80 mm. The morphology was oval or round, 37 cysts were monolocular, 8 were plurilocular. In 17 cases the authors noticed a reduction and a displacement of the corticals, but never discovered a pathological fracture. During the observed period an increase in growth of lesions was not found in the follow-up of 14 out of 44 patients.

The personal data were compared to those of the literature where the authors found a larger incidence of patients with symptoms and a history of trauma and cementofibrousdysplasia. The authors suggested that the real incidence of empty cysts is higher than that of the literature. On the basis of personal experience empty cysts are very stable. Therefore, it is questionable if oral surgery should be avoided when radiological picture is certain.