Cementoma

CEMENTOMA, a neoplasm constructed from tissue similar to the cementum of tooth roots, and therefore classified under odontogenic tumors (see). In the literature, cementomas are considered as odontomas (see) with unilateral development: while the elements forming enamel and dentin perish, the cementoplastic function is preserved (Siegmund u. Weber). Cementomas occur very rarely; Siegmund and Weber observed 3 cases. The neoplasm is of round shape, usually located in the ascending branch of the lower jaw and appears under the microscope as cementum-like bone trabeculae; the latter partly merge with each other, and are partly separated by small layers of connective tissue stroma, directly continuing into osteoid tissue. In one of the 3 cases, these authors, along with masses of cementum, found several small cysts lined with flat epithelium and filled with fluid containing cholesterol crystals, which confirms the belonging of cementomas to odontomas. The characteristic localization of cementomas in the area of the lower wisdom teeth also speaks for this. In the other two cases with a cellular stroma, Siegmund and Weber note some similarity with osteoid sarcomas or with pictures observed in the sclerosing form of local fibrous osteitis*. Romer mentions one case of a root odontoma consisting only of cementum: the tumor mass, containing blood vessels, directly passed into the avascular layer of hypertrophic cementum on the root surface. Ryvkind described in detail a case of cementoma removed from a 21-year-old man; macroscopically, the tumor fully corresponded to the concept of a root odontoma and had a typical localization (fig. 1): a horizontally positioned W*2 Ш- "^; 40...

«*p f%; Figure 1. 1-crown of wisdom tooth, fused with the second molar; 2-areas of bone resorption; £-cementoma. Figure 1. 1-crown of wisdom tooth; a-roots of wisdom tooth; Z-cementoma. Figure 3. Mass of cementoma: 1-large and small cementicles, embedded in bone substance (g). Figure 4. Mass of cementoma: J-cementicles; 2-bone substance; 3-vessels. (According to the author's original drawings.) wisdom tooth fused by its crown with the second molar; instead of the roots of the wisdom tooth, there is a bumpy tumor of hard tissue. Under the microscope, the following picture was found (fig. 2): between the malformed roots of the wisdom tooth is located a tumor mass representing a conglomeration of cementicles. The latter are embedded in bone tissue containing a small number of blood vessels. Part of the cementicles has a typical structure - round areas of acellular cementum containing sharply calcified 'nuclei' in the center (fig. 3). Some cementicles are built from bone-like tissue containing cells (fig. 4). The mass of the neoplasm in places is fused with the cementum of the wisdom tooth roots. In this case, there was fusion of three teeth: the wisdom tooth, the second molar, and a supernumerary tooth (not visible in fig. 1), and not only dentin but also the pulp cavities of all three teeth merged into each other. Thus, here there was a violation of development during the laying of the second molar (age 8-10 months), which, taking into account the typical localization, brings this case closer to odontomas. Formations similar to cementomas can arise on the basis of chronic inflammation in the paradental area (Euler-Meyer); they are close to cementexostoses - areas of secondary cementum, sharply protruding at some place along the root and sometimes complicating tooth extraction. Since cementomas cannot be clinically recognized and are diagnosed as odontomas (see) or osteomas, there are no specific treatment methods for cementomas. A neoplasm accidentally discovered during tooth extraction or removed during an operation for an odontoma only shows the structure of cementoma upon histological examination.