Noncontrast transverse CT images of the skull of the horse described in Figure 1. A—Within the ventral aspect of the left guttural pouch, there is a soft tissue–attenuating, smoothly marginated, irregularly shaped mass (dashed line) that has numerous gas bubbles throughout its parenchyma. The mass is causing rightward deviation and severe narrowing of the nasopharynx (white arrow) and laryngopharynx. B—Within the right sphenopalatine sinus, there is a soft tissue–attenuating, irregularly marginated, and irregularly shaped mass (asterisk). C—The mass is causing irregularly marginated periosteal proliferation and permeative lysis of the adjacent right proximal hamulus of the pterygoid bone, ethmoid bone, and maxillary bone (black arrows) with complete cortical destruction and a long zone of transition, consistent with an aggressive lesion. D—Cross-sectional necropsy image sliced at a level similar to CT images B and C, illustrating the sphenopalatine mass (asterisk) located medial to the ramus of the mandible (white arrow) and ventral to the right side of the calvarium (pound sign). The globe has been removed, and periorbital fat is seen in its place (ampersand). The horse’s right side is toward the left of the images. Images A and B are displayed in a soft tissue window (window width, 400 HU; window level, 50 HU), while image C is displayed in a bone window (window width, 4,000 HU; window level, 500 HU). All CT images were obtained with settings of 120 kVp, 50 mA, 7,400-millisecond exposure time, 2-cm slice thickness, 512 X 512 matrix, and an 18-cm field of view.
Citation: Journal of the American Veterinary Medical Association 261, 3; 10.2460/javma.22.11.0514