Abstract
Nasal dermoids are uncommon developmental abnormalities. Median upper lip fistulas are even rarer and recognized as a separate pathology. The authors present the unusual case of a child with a sinus on the philtrum of the upper lip and a sinus tract passing all the way to the anterior skull base through the nasal septum. The authors propose that nasal dermoids and medial upper lip fistulas have a common aetiology, and may be the same entity. The authors suggest they should all be managed like nasal dermoids and have MRI scanning prior to theatre. If the lesion extends into the nose, excision by external rhinoplasty is the preferred option.
Nasal dermoids are uncommon but may present as a midline nasal swelling. They are present in 1:20,000 to 1:40,000 live births . They have an embryological origin and it is theorized that if developing skin adheres to the fibrous nasal capsule it may be pulled posteriorly and superiorly forming an epithelial tract to the skull base . As a result of the embryological origins the nasal dermoid cyst or pit can present at any point in the midline of the nose towards and including the anterior cranial fossa. A tract can exist from the nasal dorsum to the anterior cranial fossa. Reports of nasal dermoid sinus cysts date back to 1829 . They usually present at birth but diagnosis is sometimes delayed. At the time of presentation there may be a cyst within the tract, which can change in size, and there may be discharge from a sinus . There is a significant rate of spontaneous infection with nasal dermoids and given the possibility of intracranial extension this creates a risk of meningitis or frontal bone osteomyelitis .
Given that there may be communication with the anterior skull base or a nasal dermoid within the anterior skill base, preoperative imaging is strongly recommended. This provides invaluable information for surgical planning .
Congenital median sinuses or fistulas of the upper lip are rare and have been thought to represent ectodermal inclusion . There is a similar theory that nasal dermoid sinus cysts are formed by ectodermal inclusion . Median upper lip fistulas have been described entering the oral cavity and extending to the nasal spine .
The authors present a case of a patient with a nasal dermoid who presented with a median upper lip sinus. This case raises issues about how patients with median upper lip sinuses should be managed.
Clinical case
A 2-year-old boy presented to the emergency department following a nasal injury as a result of a fall. The attending doctor noticed a discharging sinus in his upper lip and referred him to the Ear, Nose and Throat (ENT) department. He had only one episode of discharge from the sinus and was otherwise fit and well. On examination, there was a small sinus in the philtrum but no nasal swelling was present on the dorsum of the nose. Intraoral examination was normal. Figure 1 shows the punctum on the philtrum.
A magnetic resonance imaging (MRI) scan revealed a tract passing from the philtrum superiorly and posteriorly within the nasal septum. There was associated widening of the nasal septum. The tract extended to the crista galli, which was also widened ( Fig. 2 ). The dura was intact at the time of resection.
The lesion was excised using the external rhinoplasty approach. A small incision around the sinus opening on the upper lip permitted excision of the sinus. The external rhinoplasty incision allowed the tract to be followed superiorly and posteriorly through the septum into the crista galla. Figure 3 shows the sinus tract and punctum being excised from the philtrum and the tract being followed to the nasal spine. In theatre, a tract from the upper lip extending into the anterior cranial fossa was confirmed.
There were no intraoperative or postoperative complications. Both wounds healed well and the nasal shape was not affected ( Fig. 4 ). There has been no evidence of recurrence during the 6 month follow up. Pathology confirmed the tissue removed was a dermoid.
