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PRACTICAL DENTISTRY | A B E C D A Figure 12. (A) Intraoral radiograph of the left mandible of a cat with advanced squamous cell carcinoma; there is extensive bony inva- sion and a "moth eaten" appearance. (B) Intraoral radiograph of the mandibular incisors of a dog with melanosarcoma; there is extensive bony invasion and a "moth eaten" appearance, which is indicative of this type of tumor. (C) Intraoral radiograph of the mandibular incisors of a dog with fibrosarcoma (same patient in Figure 6); there is extensive bony invasion. However, the margins of the teeth that have "moved" are fairly distinct, which is more indicative of a benign lesion. Compare this figure to Figure 11B—these figures demonstrate that two very different tumors can look very similar radiographically. (D) Intraoral radiograph of the maxilla of a cat with advanced squamous cell carcinoma; note the extensive bony invasion without movement of the maxillary canine. The "spikey" appearance of the apex of the canine is further evidence of a highly malignant process. (E) Intraoral radiograph of the right mandible of a dog with fibrosarcoma; there is extensive bony invasion and signifi- cant periosteal reaction. destruction (Figures 12A and 12B).8 display a mottled "moth eaten" appearance, Initially, the bone will but radiographs late in the disease course reveal a complete loss of bone (the teeth appear to "float" in space) (Figures 12C and 12D). If the cortex is involved, an irregular periosteal reaction is often seen (Figure 12E).8 Cystic structures appear as radiolucent areas with smooth bony edges (Figure 13A).8 Similar to other benign growths, they grow by expansion and displace other structures (eg, teeth). Den- tigerous cysts are typically seen as a radiolucent structure centered on the crown of an unerupted tooth (Figure 13B).8 Aspiration & Biopsy Fine-needle aspiration is use- ful to differentiate inflammation from neoplasia, and can poten- tially determine tumor type. Histopathologic testing is always necessary for accurate diagnosis of oral masses and prior B Figure 13. (A) Intraoral radiograph of the patient in Figure 9; the radicular cyst (arrow) is obvious, surrounding the maxillary first molar. (B) Intraoral dental radiograph of the patient in Figure 8; the dentigerous cyst has destroyed the majority of the mandible in the area, resulting in significant tooth movement and weakening of the jaw, which predis- poses the area to fracture. The unerupt- ed premolar is seen at the top left. to definitive therapy since, as mentioned earlier, benign and malignant tumors can appear clinically and radiographically similar (compare Figure 11B to Figure 12C).3 Additional Diagnostics Additional diagnostic tests for question- able cases include: UÊ om«liÌiÊLloo`Ê«>nil July/August 2012 Today's Veterinary Practice 55 Introduction to Oral Neoplasia in the Dog & Cat