Nasolabial Cyst

§ overviewOverview

A soft-tissue, non-odontogenic developmental cyst located in the nasolabial fold, external to the maxillary bone, arising from epithelial remnants along the embryonic fusion of the medial nasal, lateral nasal and maxillary processes — or, per current theory, from misplaced nasolacrimal duct epithelium.

§ icdICD Classification

ICD-10 K09.8

§ etiologyEtiology

• 01Developmental — misplaced epithelium of the inferior nasolacrimal duct (currently favoured theory)
• 02Historical: entrapped ectoderm at fusion of medial nasal, lateral nasal and maxillary embryonic processes
• 03Occasional trauma or infection as triggers for enlargement

§ riskRisk Factors

• 01Female sex
• 02Middle age
• 03Family history (occasional)

§ geneticsGenetics & Molecular Biology

• 01Sporadic; no confirmed germline association

§ epidemiologyEpidemiology

Rare — < 0.7% of all maxillofacial cysts. Peak: 4th–5th decade. F:M ≈ 4:1. ~10% bilateral. More common in Black and Hispanic populations.

§ pathogenesisPathogenesis

Epithelial rests from either the nasolacrimal duct or the embryonic facial fusion line proliferate to form a cystic cavity in the soft tissue of the upper lip/nasal base. Slow expansion by mucus secretion and osmotic pressure elevates the ala and obliterates the nasolabial fold; underlying maxilla may show a smooth saucer-shaped depression from pressure remodelling but no true bone defect.

§ clinicalClinical Features

• 01Slowly enlarging, painless swelling of the upper lip lateral to the midline
• 02Obliteration of the nasolabial fold
• 03Elevation of the ala nasi and lifting of the nasal tip
• 04Bulging into the floor of the nasal vestibule
• 05Fluctuant on palpation
• 06Nasal obstruction if large

§ signsSigns & Symptoms

• 01Cosmetic asymmetry
• 02Nasal airway obstruction on the affected side
• 03Occasional pain if infected
• 04Rarely intra-nasal discharge

§ differentialDifferential Diagnosis

• 01Radicular cyst of maxillary lateral incisor / canine (intra-osseous)
• 02Furuncle of nasal vestibule
• 03Salivary gland tumour of upper lip
• 04Dermoid or epidermoid cyst
• 05Nasopalatine cyst (bony, midline)
• 06Odontogenic infection / abscess

§ criteriaDiagnostic Criteria

• 01Soft-tissue swelling of the upper lip / nasal alar base
• 02Absence of intra-osseous radiolucency
• 03Confirmatory MRI / CT showing well-defined soft-tissue cyst
• 04Histology: pseudostratified ciliated columnar (respiratory) epithelium ± goblet cells

§ histopathHistopathology

• 01Pseudostratified ciliated columnar (respiratory) epithelium in most cases
• 02Goblet cells commonly present
• 03Focal areas of stratified squamous epithelium from metaplasia
• 04Thin fibrous capsule with mild chronic inflammation
• 05No cartilage, muscle or true glandular structures in wall — distinguishes from teratoid lesions

§ radiographicRadiographic Features

• 01Plain radiographs typically NORMAL — cyst is extra-osseous
• 02Occasional smooth saucer-shaped pressure resorption of anterior maxilla
• 03Occlusal radiograph with radiopaque contrast (historic Klestadt technique) demonstrates the soft-tissue cavity

§ opgOPG Findings

• 01Usually unremarkable; loss of nasal floor cortex if very large

§ cbctCBCT Findings

• 01Confirms absence of intra-osseous involvement; may show maxillary pressure defect

§ ctCT Findings

• 01Well-defined, non-enhancing, hypodense soft-tissue mass in the nasolabial region
• 02May bulge into the nasal cavity floor

§ mriMRI Findings

• 01T1 hypointense (or hyperintense if proteinaceous), T2 hyperintense; peripheral rim enhancement of the wall — modality of choice

§ usgUltrasonography

• 01Anechoic well-circumscribed lesion with posterior enhancement; useful as first-line non-invasive study

§ investigationsInvestigations

• 01Vitality testing of adjacent maxillary teeth (must be vital)
• 02MRI or CT to confirm soft-tissue location
• 03USG for a first pass
• 04Aspiration — mucoid fluid
• 05Excisional biopsy definitive

§ labsLaboratory Findings

• 01Aspirate: mucoid, non-purulent unless infected

§ ihcIHC / Special Stains

• 01CK7 / CK8 / CK18 highlight respiratory-type lining
• 02MUC5AC / MUC5B positive goblet cells

§ whoWHO Classification

WHO 2022 Classification of Head & Neck Tumours: Non-odontogenic developmental cyst — Nasolabial cyst (soft-tissue).

§ classificationClassification

• 01Unilateral (~90%)
• 02Bilateral (~10%)

§ planTreatment Planning

• 01Confirm extra-osseous location on MRI/CT
• 02Assess for nasal floor involvement
• 03Choose sublabial vs endoscopic transnasal marsupialisation approach

§ treatmentTreatment

• 01Complete surgical excision via sublabial approach is the gold standard
• 02Endoscopic transnasal marsupialisation is a minimally invasive alternative with low morbidity and comparable recurrence
• 03Aspiration alone is not curative

§ medicalMedical Management

• 01Antibiotics only for secondary infection
• 02Analgesics as needed

§ surgicalSurgical Management

• 01Sublabial incision → careful dissection preserving the nasal floor mucosa → complete cyst removal
• 02Alternative: endoscopic transnasal marsupialisation — creates a permanent window into the nasal cavity, faster recovery
• 03Meticulous haemostasis; primary closure

§ reconstructionReconstruction Options

• 01Not usually required as no bony defect
• 02Nasal floor mucosa closed primarily if perforated

§ complicationsComplications

• 01Nasal floor perforation (oronasal fistula)
• 02Infection
• 03Post-op oedema and paraesthesia of upper lip
• 04Recurrence if incomplete excision
• 05Rare mucocele formation

§ recurrenceRecurrence Rate

< 5% after complete sublabial excision; slightly higher after marsupialisation but with lower morbidity.

§ followupFollow-up Protocol

• 01Clinical review at 1 week, 1 month and 6 months
• 02Endoscopic follow-up after transnasal marsupialisation to assess window patency
• 03Annual review for 2 years

§ prognosisPrognosis

Excellent with complete excision. No malignant potential documented.

§ preventionPrevention

• 01None — developmental cyst

§ examKey Examination Points

• 01Palpate the nasolabial fold bimanually (intra-oral + extra-oral)
• 02Look for obliteration of the nasolabial groove and elevation of ala nasi
• 03Bulge into nasal vestibule strongly suggests nasolabial cyst

§ revisionQuick Revision Summary

• 01Extra-osseous non-odontogenic cyst
• 02Female middle-aged predominance
• 0310% bilateral
• 04Respiratory epithelium with goblet cells
• 05MRI diagnostic
• 06Sublabial excision curative

§ vivaBDS Viva Questions

• 01Define nasolabial cyst.
• 02What are the theories of origin?
• 03Why does the ala nasi lift?
• 04How do you differentiate from a radicular cyst of the canine?
• 05Histological lining?
• 06Imaging modality of choice?
• 07Surgical approaches and their pros/cons?
• 08Recurrence rate?
• 09What is Klestadt's contribution?
• 10Is malignant transformation known?

§ bdsBDS Professional Examination

• 01Short essay: Nasolabial cyst — pathogenesis, features, and management.
• 02Short note: Differences between nasolabial and nasopalatine cyst.
• 03Short note: Fusion cysts of the face.

§ fcpsFCPS Residency Questions

• 01Compare open sublabial excision with endoscopic transnasal marsupialisation for nasolabial cyst.
• 02Discuss the embryology of facial development and its relevance to fissural cysts.

§ pearlsClinical Pearls

• 01A soft-tissue swelling that lifts the ala nasi with vital adjacent teeth is a nasolabial cyst.
• 02Endoscopic marsupialisation is faster with less morbidity — offer as an option to modern patients.

§ mnemonicsMnemonics

• 01Klestadt = Klean out from Klestadt approach (sublabial)

§ readingSuggested Reading

• 01Su C-Y et al. Endoscopic marsupialisation of nasolabial cyst. Laryngoscope 2005.
• 02Roh JL et al. Nasolabial cyst: clinicopathologic analysis. J Oral Maxillofac Surg 2009.
• 03Shear M, Speight PM. Cysts of the Oral and Maxillofacial Regions, 4e.

§ differentialDifferential Comparison

§ mcqsMCQs — Assessment (20)

§ relatedRelated Diseases

References

1. WHO Classification of Head and Neck Tumours, 5e (2022)
2. Neville BW et al. Oral and Maxillofacial Pathology, 4e
3. Shafer WG et al. Textbook of Oral Pathology, 9e
4. Peterson LJ. Contemporary Oral & Maxillofacial Surgery, 7e