Mandible / maxilla
Fissural and other non-odontogenic cysts
Nasopalatine cyst

Author: Anthony Martinez, M.D. (see Authors page)
Editor: Kelly R. Magliocca, D.D.S., M.P.H.

Revised: 21 June 2018, last major update July 2015

Copyright: (c) 2004-2018, PathologyOutlines.com, Inc.

PubMed Search: Nasopalatine cyst [title]

Cite this page: Martinez, A. Fissural and other non-odontogenic cysts: nasopalatine cyst. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/mandiblemaxillanasopalatine.html. Accessed July 22nd, 2018.
Definition / general
  • Most common intraosseous, non-odontogenic cyst of jaw (maxilla)
Terminology
  • Median anterior cyst
  • Midline maxillary cyst
  • Anterior median palatine cyst
  • Incisive canal cyst
  • Incisor duct cyst
Epidemiology
  • Occurs in ~1% of population
  • Represents 1.7 - 11.9% of all jaw cysts
  • Usually adults, peak prevalence in fourth and fifth decades
  • More common in males (ranges in literature from slightly more common to up to 3x more common in males than females)
Sites
  • Exclusively in maxilla, located in anterior midline of hard palate
    • Occasionally can produce a midline anterior maxillary swelling if cyst erodes bone of anterior maxilla
  • Cysts can form within the incisive canal located in palatine bone behind alveolar process of maxillary central incisors
  • Some doubt the existence of median palatine cyst as a distinct entity and characterize all non-odontogenic cysts of the midline maxilla regardless of anterior or midline location, as nasopalatine duct cysts
  • Rarely, may develop within incisive papilla, the anterior soft tissue protruberance that overlies the incisive foramen
    • In this instance, is termed cyst of incisive papilla, or cyst of palatine papilla
Etiology
  • Two main theories:
    • First: originates from spontaneous proliferation of remnants of nasopalatine duct within incisive canal
      • Exact trigger that stimulates development is unknown, but factors proposed include trauma and infection
    • Second: theory now out of favor; originates from trapping of epithelial remnants during embryologic fusion between nasal cavity and anterior maxilla
Clinical features
  • Usually asymptomatic, may have swelling of palate in relation to maxillary central incisors
  • Occasionally produces a midline anterior maxillary swelling if cyst erodes bone of the anterior maxilla
  • Can present with painful swelling or drainage, or tooth root displacement
Diagnosis
  • Diagnosis dependent on clinical, radiologic and pathologic correlation
Prognostic factors
  • Although extremely rare, malignant transformation (squamous cell carcinoma) has been reported
  • Relapse rate varies but usually from 0 - 11%
  • Hyperkeratotic features associated with higher relapse rate (closer to 30%)
Radiology description
  • Differential diagnosis:
    • Enlarged incisive fossa
      • The incisive foramen by convention is not expected to exceed 6 mm
      • A radiolucency in this region with ill defined borders is regarded as a large incisive fossa
      • Distinction from a nasopalatine duct cyst can be made clinically by aspiration
    • Central giant cell granuloma
      • Can have similar radiologic findings
      • Histologic features of central giant cell granuloma consist of a proliferation of fibrous tissue, hemorrhagic focuses, hemosiderin deposits, osteoclast-like giant cells and reactive bone formation
    • Ameloblastoma
    • Keratocystic Odontogenic Tumor
    • Periapical (radicular) cyst
  • On radiograph and CT, is well circumscribed, rounded or heart shaped radiolucency of anterior maxilla
Radiology images

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Heart shaped radiolucent lesion

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Expansile maxillary alveolus

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Well defined round radiolucent area

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Well defined radiolucency

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Homogeneous high intensity area

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Saggital / axial CT images

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Axial sections of CT

Case reports
Treatment
  • Surgical excision is most common, but marsupialization has also been performed
Clinical images

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Fissural cysts

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Teeth and hard palate

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Intraoral swelling

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Intraoperative view, cystic area

Gross description
  • Variable size, mean diameter ~1.5 cm
  • Sectioning reveals cystic and fibrous areas
Gross images

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Surgical specimen

Microscopic (histologic) description
  • Lined by stratified squamous epithelium alone or with pseudostratified columnar epithelium (variable cilia and goblet cells), simple columnar epithelium or simple cuboidal epithelium
  • Cyst wall is composed of fibrous tissue with nerves, cartilaginous rests, arteries and veins
  • The nasopalatine duct contains the nasopalatine nerve and the terminal branch of the descending palatine artery
Microscopic (histologic) images

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Stratified squamous and pseudostratified columnar epithelium

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Flattened cuboidal epithelium

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Fibrous cyst wall with nerves

Differential diagnosis
  • Glandular odontogenic cyst:
    • Intraosseous developmental odontogenic cyst, may have ciliated or mucous cells within cystic lining
    • Should NOT have contents of incisive foramen (peripheral nerve, cartilaginous rests, muscular vascular channels)
  • Nasolabial (nasoalveolar) cyst:
    • Soft tissue (non-intraosseous) cyst with histologic features similar to nasopalatine cyst
    • Occurs in soft tissues of upper lip lateral to midline
    • Should not have contents of incisive foramen (peripheral nerve, cartilaginous rests, muscular vascular channels)
  • Periapical (radicular) cyst:
    • Most common inflammatory odontogenic cyst
    • Lined by stratified squamous epithelium of variable thickness, often with scattered ciliated cells
    • Derived from rests of Malassez
    • In nasopalatine cysts, the lamina dura is intact and the pulp is usually vital, but radicular cysts are associated with a pulpless tooth and involve a portion of the root, usually with loss of continuity of the lamina dura
  • Surgical ciliated cyst:
    • Post-operative "complication" with cystic expansion of respiratory epithelium within maxilla, may have ciliated or mucous cells within cystic lining
    • Usually located in posterior maxilla and lacks contents of incisive foramen (peripheral nerve, cartilaginous rests, muscular vascular channels)