Simple bone cyst versus odontogenic keratocyst:: differential diagnosis by digitized panoramic radiography

Objectives: To identify the contour and pixel grey levels of simple bone cyst (SBC) and odontogenic keratocyst (OKC) images that might contribute to differentiating between the two lesions. Methods: Panoramic radiographs of 32 SBC and 20 OKC were digitized and analysed by six examiners. The contours of the images were classified as indistinct, distinct without a sclerotic border, and distinct with a sclerotic border. The presence or absence of scalloping and the pixel grey levels of the radiolucent part of the images were also determined. Results: The sclerotic border was more frequent in the OKC, especially in the posterior segment (P = 0.0301). The presence of scalloping was more frequent in the superior segment of the SBC (P = 0.0295). The pixel values were higher in the OKC than in the SBC images (P = 0.00134). Conclusions: Details about the contour and pixel grey levels of OKC and SBC assist in the diagnosis of these lesions.