Computed tomography findings and surgical outcomes of dermoid sinuses: a case series.

OBJECTIVE: This case series describes the computed tomography (CT) and surgical findings of nine dogs with dermoid sinuses.
METHODS: Medical records were reviewed and summarised.
RESULTS: CT with intravenous contrast showed a superficial, peripherally contrast-enhancing, fluid-filled structure with a contrast-enhancing, soft tissue-attenuating tract that extended from the skin through the dorsal midline soft tissues, often to the level of the nuchal ligament. The tract often extended in an oblique direction to the nuchal ligament, but the tract ventral to the nuchal ligament, found at surgery, was not always discernible on CT. The dermoid sinuses were excised from all dogs. At surgery, the tract often extended ventral to the nuchal ligament, terminating on the vertebra. The most ventral aspect of the tracts involved a fibrous strand extension of the sinus, which was not discernible on CT.
CONCLUSION: Preoperative CT facilitated the diagnosis of a dermoid sinus and directed surgical planning; however, careful dissection beyond the nuchal ligament is imperative for complete excision.