Rare Shiba Inu dermoid sinus case highlights spinal surgery planning
Bottom line
Version 1 — Brief
A new case report in Veterinary Surgery describes successful treatment of a rare dermoid sinus variant in a 16-month-old spayed female Shiba Inu with thoracic spina bifida. According to the report, the dog had a type V-variant dermoid sinus with overlap features of type VI, and surgeons achieved complete excision using dorsal laminectomy and partial durectomy. The dog recovered fully, with no recurrence reported at 12 months. The authors say this is the first published case in a Shiba Inu with this specific dermoid sinus variant plus a concurrent spinal anomaly. (onlinelibrary.wiley.com)
Why it matters: Dermoid sinus is uncommon outside predisposed breeds, but when it tracks toward the vertebral canal or overlaps with spina bifida, the stakes rise because of infection risk, neurological compromise, tethering, and the need for complete surgical removal. For veterinary teams, this case reinforces the value of advanced imaging and careful surgical planning when a congenital midline lesion may have deeper spinal involvement. Prior reports in dogs with dermoid sinus and spina bifida have also found good outcomes after surgery, but incomplete excision can lead to recurrence. (acvs.org)
What to watch: Watch for whether this case influences how clinicians classify borderline type V/VI lesions and whether more breed-specific reports emerge in Shiba Inus and other non-Rhodesian Ridgeback dogs. (pmc.ncbi.nlm.nih.gov)
Key facts
- Article type
- Case report
- Journal
- Veterinary Surgery
- Patient
- 16-month-old spayed female Shiba Inu
- Condition
- Type V-variant dermoid sinus with type V/VI overlap features
- Concurrent anomaly
- Thoracic spina bifida
- Treatment
- Complete excision via dorsal laminectomy and partial durectomy
- Outcome
- Complete recovery, with no recurrence at 12 months
- Notable claim
- First reported Shiba Inu case with this dermoid sinus variant and concurrent spinal anomaly
Version 2 — Full analysis
A newly published case report adds a rare Shiba Inu presentation to the veterinary literature: a 16-month-old spayed female dog with a type V-variant dermoid sinus showing type V/VI overlap features, alongside thoracic spina bifida, was treated successfully with complete surgical excision. The procedure involved dorsal laminectomy and partial durectomy, and the authors reported complete recovery with no recurrence at 12-month follow-up. They describe it as the first reported Shiba Inu case with this specific dermoid sinus variant and concurrent spinal anomaly. (onlinelibrary.wiley.com)
That matters partly because dermoid sinus classification has become more nuanced over time. Classic veterinary descriptions recognized types I through IV, with later literature adding type V as a closed epithelial-lined cyst with no skin opening and type VI as a tract that reaches the supraspinous ligament and continues to the dura via a fibrous band. More recent case literature has also highlighted lesions that don’t fit neatly into a single category, including subtype and overlap descriptions. (pmc.ncbi.nlm.nih.gov)
The Shiba Inu report also lands in the context of a small but growing body of literature linking dermoid sinus with spinal malformations. A 2011 case series described concomitant dermoid sinus and spina bifida in three dogs and a cat, with good surgical outcomes in the dogs. More recently, a 2024 report described type I and type IV dermoid sinus with cervical spina bifida in a mixed-breed dog, and a 2023 English bulldog case documented dermoid sinus with distal dilation, meningocele, and spina bifida. Together, those reports suggest clinicians should think beyond a superficial skin lesion when a dorsal midline abnormality is paired with pain, neurologic deficits, or vertebral malformations on imaging. (onlinelibrary.wiley.com)
There’s also Shiba Inu-specific context. In 2022, investigators reported a different Shiba Inu case involving a type IV spinal dermoid sinus with vertebral malformations, granulomatous meningomyelitis, paraparesis, pain, and urinary incontinence. That dog improved after hemilaminectomy and excision. The new Veterinary Surgery case appears less about infectious granulomatous change and more about defining and successfully removing a rare variant lesion associated with spina bifida, but both reports underscore that Shiba Inus can present with clinically important spinal dermoid disease, even though the condition is better known in Rhodesian Ridgebacks. (pmc.ncbi.nlm.nih.gov)
Expert and specialty guidance broadly supports the management approach described here. The American College of Veterinary Surgeons notes that dermoid sinuses causing discharge, infection, or neurologic signs should be treated with surgical excision, and warns that failure to remove the lesion completely can result in redevelopment. Imaging literature likewise shows CT and MRI can help define tract depth, bony defects, and communication with the dura before surgery. (acvs.org)
Why it matters: For veterinary professionals, this case is a reminder that congenital dorsal midline lesions deserve a neurologic and imaging workup when the anatomy or clinical signs don’t fit a simple cutaneous cyst. The overlap between dermoid sinus subtypes and associated anomalies such as spina bifida can change both prognosis and surgical approach, including whether laminectomy, durotomy, or durectomy may be needed. In referral settings, that means coordinating dermatology, surgery, neurology, imaging, and pathology early. In general practice, it means recognizing when a “skin lesion” may actually be a spinal case. (pmc.ncbi.nlm.nih.gov)
The report may also have value for classification and case recognition. A type V lesion, by definition, lacks a skin opening, while type VI includes a superficial sinus tract with deeper fibrous connection to the dura. A V/VI overlap case suggests some lesions may sit on the boundary between accepted categories, which could affect how clinicians describe them in records, teach them to trainees, and compare outcomes across case reports. That’s an inference from the published classification framework and the authors’ description of overlap, rather than a formal consensus change. (pmc.ncbi.nlm.nih.gov)
What to watch: The next step is whether additional reports clarify how often these overlap lesions occur, whether Shiba Inus represent an emerging signal or just a rare coincidence, and whether future reviews refine dermoid sinus classification around spinally associated variant cases. (frontiersin.org)