Central Tumors of the Lower Jaw

Abstract

IN the X-ray diagnosis of bone tumors it is as important to realize the limitations of the X-ray as it is to recognize those diagnostic characteristics which the film reveals. With the aid of the X-ray the central bone-expansive tumors of the lower jaw can be differentiated from periosteal lesions and osteomyelitis. But central bone-destructive tumors of the jaw include (1) the root or alveolar abscess, (2) its derivatives—the granuloma and root cyst, (3) the dentigerous cyst, (4) the adamantine epithelioma, (5) the giant-cell tumor, (6) the fibroma and fibrosarcoma, and (7) rarer lesions such as carcinoma arising from the gums, and myxoma. After recognizing a lesion as central, further identification is sometimes difficult. This problem of differential diagnosis is the topic of the following pages, based on a study of the jaw tumors in the Surgical Pathological Laboratory of the Johns Hopkins Hospital. The root abscess.—The most frequent finding in a routine X-ray examination of the teeth is the presence of periapical areas of bone absorption about non-vital teeth whose apices may be more or less eroded (Figs. 1 and 2). This characteristic picture of a locally symptomless lesion is usually called a root or alveolar abscess. If, however, the tooth be extracted, no pus, but, rather, a granuloma or sometimes a root cyst will be found. The granuloma is the sequel of an acute apical peridontitis in which the intense inflammation has subsided, with the formation of a nodule of chronic granulation tissue. Strands of squamous epithelium, arising from the irritated epithelial rests remaining about the tooth root, are a frequent finding in microscopic sections of such a granuloma. When cystic degeneration occurs in these epithelial sprouts a dental cyst lined by stratified squamous epithelium is the result (Fig. 3). The granuloma is of small size, while the root cyst may grow by continuous desquamation of epithelial cells and expand the jaw bone to such an extent that parchment crepitation may be elicited on pressure. The recognition of the so-called root abscess is most important, not only because root abscesses may give rise to osteomyelitis or act as foci of infection in various chronic conditions but because early malignancy must be excluded. The roentgenogram of a root abscess is quite characteristic. When, however, the film shows an atypical area more films should be taken for further study, and, upon extraction of the tooth, sections should be made from tissue adherent to the tooth or from the root socket. It should be unnecessary to note that teeth should not be extracted without first taking X-ray films. This laboratory contains many cases of tooth extraction in early malignancy performed with the hope of relieving local symptoms in which either no X-ray has been made or else it has been incorrectly diagnosed as a root abscess. In these early cases the X-ray, supplemented by the microscope, performs an invaluable service.