Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

624 Small Animal Radiolo g y and Ultrasono graphy
Fig. 5-15 A 9-year-old male
German Shepherd dog with apparent
neck pain. Meticulous physical
examination revealed that pain
could be elicited by deep palpation
of the base of the skull behind the
right ear. A, The right lateral oblique
view revealed that the left middle ear
and jugular process (white arrow)
were normal. There is minimal soft
tissue in this area. B, The left lateral
oblique view revealed a normal middle
ear. The jugular process (solid
white arrow) has irregular cortical
surfaces, and irregularly round calcifications
are seen over the process.
There is a large soft-tissue mass
(open white arrows) associated with
the area. Differential diagnoses
include primary bone tumor, softtissue
tumor affecting adjacent bone,
metastatic neoplasia, and infection.
Diagnosis: Osteosarcoma arising
from the jugular process.
A
B
tissues around the teeth. Although the tumors may displace teeth, they rarely cause tooth
loss. Malignant tumors are more likely to cause irregular or poorly marginated bony
destruction, while benign tumors more often result in smooth, distinctly marginated
bony destruction. 51 However, no set of radiographic findings can be considered pathognomonic.
66,67 Squamous cell carcinoma usually causes lysis in dogs, and in cats there is lysis
of bone and frequently a pattern of punctate calcifications in the bone and associated soft
tissues (Fig. 5-18). Those melanomas that involve bone usually result in a smoothly bordered
lytic lesion positioned eccentrically on the bone. Epulis, a tumor arising from the