Nasolabial Cyst

Nasolabial cyst, also called nasoalveolar cyst, is a rare non-odontogenic developmental cyst of soft tissue in the nasolabial fold, beneath the ala of the nose and the upper lip. It does not originate in the bone or a tooth.

It accounts for under 1% of jaw cysts, most commonly in women in the fourth and fifth decades, with a female to male ratio of about 3 to 1 or more. About 10% are bilateral.

Pathophysiology. The leading theory is origin from remnants of the nasolacrimal duct epithelium trapped at the fusion of the maxillary, medial and lateral nasal processes. Others suggest an origin from the nasal vestibule epithelium.

The cyst grows slowly by secretion, and it can cause pressure erosion of the underlying maxilla without invasion.

A painless swelling of the nasolabial fold that lifts the ala of the nose and fills out the nasal vestibule floor, and obliterates the nasolabial groove, with fullness in the labial vestibule. Nasal obstruction can occur.

Infection produces pain, redness and discharge, and the cyst may drain into the nose or mouth. The teeth are vital and the swelling is separate from the bone on palpation. Bimanual palpation of the lesion between a finger in the mouth and one on the skin is helpful.

• Clinical diagnosis from the typical site and fluctuant swelling.
• CT or MRI: a well defined, homogeneous cystic mass in soft tissue at the nasal floor with a saucer shaped erosion of the anterior maxilla in some. MRI shows signal that depends on protein content.
• Ultrasound for superficial lesions.
• Pulp sensibility tests to exclude dental causes.
• Aspiration to give a mucoid or serous fluid, and histology of the excised cyst: pseudostratified columnar epithelium with goblet cells, or squamous or cuboidal epithelium, often with cilia.

Differential diagnosis.

• Odontogenic infection and radicular cyst of an incisor
• Nasopalatine duct cyst
• Dermoid or epidermoid cyst
• Furuncle or abscess of the vestibule
• Lipoma and minor salivary gland tumour
• Fibrous dysplasia and other bone lesions
• Nasal vestibule mucocele

• Complete surgical excision through a sublabial incision, with dissection of the cyst from the nasal mucosa. Rupture or incomplete removal leads to recurrence, which is uncommon, at about 1 to 5%.
• Endoscopic transnasal marsupialisation is an option for selected cases, with a nasal packing or stent for a few days and a lower rate of nasal vestibule complications.
• Aspiration alone is followed by recurrence.
• Acute infection: amoxicillin with clavulanic acid 500 mg and 125 mg orally three times daily for 5 days, or doxycycline 100 mg twice daily in penicillin allergy. Drain an abscess.
• Analgesia: paracetamol 1 g every 6 hours (maximum 4 g daily) with ibuprofen 400 mg every 8 hours with food.

Monitoring. Review at 2 weeks and 3 months for healing, nasal patency and recurrence. Repeat imaging if swelling reappears.

Referral and escalation. Refer to oral and maxillofacial or ENT surgery for excision. Urgent referral for infection with spread, rapid growth or unusual histology.