A "gullwing sign" on magnetic resonance imaging of extradural spinal tumors in dogs and cats allows prioritization of round cell neoplasia.

Extradural neoplasms are the most common spinal tumors in small animals. A bilobed appearance of ventral extradural spinal lesions ("gullwing sign") on MRI has been described with various conditions. The objective of this retrospective study was to determine if a "gullwing sign" is more common with certain types of extradural tumors. MRI studies of dogs and cats with extradural spinal neoplasms were reviewed for the presence of a "gullwing sign". Statistical analysis was performed to evaluate a possible relationship between tumor class and the presence of a "gullwing sign". Sixty-six cases were included (5 epithelial, 31 mesenchymal, 4 neuroendocrine, and 26 round cell tumors). A "gullwing sign" was identified in 12 of 66 cases (18.2%) and was significantly more common with round cell neoplasia than other tumor types (P < .001; OR = 28.6, 95% CI [3.4, 241.1]). This information may aid radiologists in prioritizing differential diagnoses for extradural tumors in small animals.