Nasal Dermoid Sinus Cysts in the Dog

Abstract

This is a new condition that should be added to the surgical differential diagnosis for a discharging sinus over the external nares in dogs.

Nasal dermoid cyst extending through the frontal bone with no sinus tract in a Dalmatian

“…To our knowledge, this is the first reported case of a NDSC with no dorsal opening but with a tubular tract extending to the lamina perpendicularis ethmoidalis. In eight previously published cases, the reported skin opening was located at the mucocutaneous junction of the nasal planum (Anderson and White 2002, Burrow 2004, Sturgeon 2008) and between the eyes in one case (Bailey and others 2001). This “nasal pit” was considered a characteristic of NDSC in the dog and was considered similar to the “nasal pit” in human NDSC by Anderson and White (2002).…”

“…Nasal dermoid sinus cysts (NDSCs) in dogs are rare congenital anomalies that result from incomplete obliteration of neuroectoderm within the prenasal space (Anderson and White 2002). In most cases, dogs are presented with a history of a swelling on the dorsal aspect of the nose and an intermittent discharge from a small opening in the midline on the bridge of the nose at the junction between the nasal planum and the skin (Anderson and White 2002). In the human embryo, the prenasal space is formed between the nasal bone and a deeper layer of cartilaginous capsule.…”

“…According to the “prenasal theory” by Pratt (1965), as the dura mater recedes from the prenasal space, it may inadvertently pull the nasal ectoderm upward and inward to form a sinus or a cyst (Rahbar and others 2003). Anderson and White (2002) suggested that NDSC in the dog had a similar pathogenesis to the condition in humans. This case report highlights a different clinical presentation of NDSC in a dog: an NDSC with extension through the frontal bone with no sinus tract.…”

Spinal dermoid sinus in a Burmese cat with paraparesis

“…It is most frequently reported in the dorsal midline with or without the malformation of vertebral bodies 1–5,7–10 . Dermoid sinuses have also been reported to occur around the cranium of other breeds of dog, where they have been found intracranially, 11 in the parieto‐occipital region, 12 and in the nose and the frontal sinus 13,14 . Dermoid sinuses that arise from these areas have been suggested as having different embryologic origins to the non‐cranial dorsal midline lesions 11–13 …”

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

“…The presumptive diagnosis of a dermoid sinus is based on typical clinical findings, particularly in a known affected breed, and includes a palpable swelling over the dorsal midline with or without an associated cutaneous fistula opening. The lesion can occur anywhere from the nose to the sacrum . The term ‘fistula’ is used because it indicates any abnormal tube‐like passage within body tissue; in this context, the dermoid cyst and the skin.…”