Computed Tomography Findings in a Case of Giant Frontal Sinus Mucopyocele in a Dog

A 16-month-old male crossbreed dog, which suffered a previous traumatic incident, was presented for evaluation of a chronic fluctuant right supraorbitary mass. On computed tomography, a well-defined, expansile, hypodense mass, showing a thin peripheral enhancement was occupying the right frontal sinus and extending into the cranial cavity. Imaging findings, bacteriological culture, and histopathology of the surgically excised mass were consistent with a frontal sinus mucopyocele. Frontal sinus mucopyocele should be included as a differential diagnosis for a well-marginated expansile frontal sinus mass, especially when present in young animals or/and associated with a previous craniofacial trauma.