Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Five The Skull 623
Fig. 5-13 A 6-year-old neutered female domestic short-haired
cat with lethargy and a marked change to aggressive behavior.
There is hyperostosis, or bony thickening, of the right side of the
calvarium (white arrow). There is an overall increased density
on the right calvarium when compared with the left calvarium.
Diagnosis: Meningioma. (From Lawson C, Burk RL, Prata RG:
Cerebral meningioma in the cat: diagnosis and surgical treatment
of 10 cases. J Am Anim Hosp Assoc 1984; 20:333.)
Fig. 5-14 A 12-year-old neutered
female domestic short-haired cat
with circling to the left and a behavior
change to increased aggression.
The frontal view revealed destruction
of the left frontal bone with
expansion laterally (white arrow).
There is a small area of hyperostosis
at the junction of the lytic process
with the less affected bone dorsally.
Differential diagnoses include primary
bone tumor, invasive meningioma,
and metastatic tumor.
Diagnosis: Meningioma. (From
Lawson C, Burk RL, Prata RG:
Cerebral meningioma in the cat:
diagnosis and surgical treatment of
10 cases. J Am Anim Hosp Assoc
1984; 20:333.)
Tumors may occur in the soft tissues adjacent to the skull. 63 Soft-tissue tumors of the
ear canal may be evident as a soft-tissue density obliterating the normally air-filled ear
canal. The most common tumors at this site are ceruminous gland carcinoma and squamous
cell carcinoma. 61,64 These also may enlarge and invade the area of the osseous bullae
(Fig. 5-16).
Tumors of the zygomatic arch are usually primary bone tumors and lytic and productive
lesions may be seen (Fig. 5-17). 62
The most common neoplastic lesions affecting the mandible and maxilla in dogs are
squamous cell carcinoma, epulis, fibrosarcoma, and melanoma. 53,65 Squamous cell carcinoma
and lymphoma are the most common in cats. Many of these tumors arise from the