Untitled Quiz

Cysts of the Oral Cavity

• A presentation on Cysts of the oral cavity
• The presentation covers various types of cysts within the oral cavity, including Nasopalatine canal, Nasolabial cyst, Globulomaxillary cyst, Median palatine cyst, Median mandibular cyst, Solitary bone cyst, Aneurysmal bone cyst, Stafne's idiopathic bone cavity, Benign cervical lymphoepithelial cyst (old name: branchial cyst), Dermoid cyst, and Mucocele (Mucous extravasation cyst and Mucous retention cyst).

Nasopalatine Canal (Duct) Cyst

• A developmental cyst arising from remnants of the nasopalatine duct
• Located midline, between and posterior to the central incisor teeth
• Cyst of the palatine papillae is a soft tissue variant

Clinical Features (Nasopalatine Canal Duct Cyst)

• Occurs in the fifth or sixth decades
• Males more commonly affected
• Usually asymptomatic unless infected; slow growing
• Detected during routine examination

Radiographic Features (Nasopalatine Canal Duct Cyst)

• Well-defined, round, ovoid or heart-shaped radiolucency with a sclerotic rim
• Located midline or displaced to one side
• Anterior nasal spine often superimposed, creating a heart-shape

Histological Features (Nasopalatine Canal Duct Cyst)

• Lining composed of stratified squamous epithelium, pseudostratified ciliated columnar epithelium or a combination of both
• Connective tissue wall contains a neurovascular bundle (small arterioles from greater and lesser palatine arteries, and nerves from the sphenopalatine nerve)

Differential Diagnosis (Nasopalatine Canal Duct Cyst)

• Periapical granuloma
• Periapical cyst

Treatment (Nasopalatine Canal Duct Cyst)

• Enucleation if small
• Marsupialization if large

Nasolabial Cyst

• Rare lesion arising in the soft tissue of the upper lip, below the ala (wing) of the nose
• Pathogenesis suggested as fissural cyst, originating from remnants of epithelium at the medial and lateral nasal processes fusion site of the maxilla.

Clinical Features (Nasolabial Cyst)

• Mostly occurs in the fourth decade
• Females more commonly affected
• May be bilateral
• Slow growth, obliterating the nasolabial fold and distorting nostrils

Histological Features (Nasolabial Cyst)

• Usually lined by pseudostratified columnar epithelium; stratified squamous epithelium and mucous cells may be present

Differential Diagnosis (Nasolabial Cyst)

• Radicular inflammatory cyst

Globulomaxillary Cyst

• A very rare cyst positioned between the roots of the maxillary lateral incisor and canine
• Pathogenesis thought to involve epithelial remnants from the joining of the globular portion of the medial nasal process and maxillary process

Radiographic Features (Globulomaxillary Cyst)

• Appears as an inverted unilocular pear-shaped radiolucency

Histological Features (Globulomaxillary Cyst)

• Usually lined by pseudo stratified columnar epithelium

Median Palatine Cyst

• Very rare lesion
• Initially thought to originate from entrapped epithelium at the fusion line of lateral palatal shelves of the maxilla
• More accepted view is that it is a posteriorly positioned nasopalatine duct cyst

Median Mandibular Cyst

• Thought to be a fissural cyst due to entrapped epithelial rests during mandible fusion in embryonic life

Solitary Bone Cyst

• Also known as simple bone cyst, traumatic bone cyst, or hemorrhagic bone cyst
• Pathogenesis unclear, possibly related to trauma causing central hemorrhage in the bone, failure of blood clot resorption, or hemodynamic disturbance
• Typically located in the mandible (between canine and ascending ramus)

Clinical Features (Solitary Bone Cyst)

• Usually seen in children and adolescents (second decade)
• Predominantly affects the mandible
• Asymptomatic; typically discovered incidentally on X-rays
• Only 25% show bone expansion

Radiographic Features (Solitary Bone Cyst)

• Highly suggestive diagnosis; well-defined unilocular radiolucency of variable size and irregular outline
• Shows scalloping or festooning outline around and between tooth roots

Histological Features (Solitary Bone Cyst)

• Surgical exploration reveals a rough, empty bony-walled cavity with no soft tissue lining
• Clear or blood-stained fluid seen in some cases

Aneurysmal Bone Cyst

• Blood-filled, pseudocyst; either a primary lesion or secondary complication of other bone lesions
• Pathogenesis is unknown; possible etiologies include trauma, or preceding primary bone lesions (fibrous dysplasia, giant-cell granuloma, or vascular malformation)

Clinical Features (Aneurysmal Bone Cyst)

• Usually seen in patients under 30 years of age
• Commonly located in the mandible's posterior portion
• Often painful, manifesting as rapidly developing swelling
• Non-pulsatile upon palpation

Radiographic Features (Aneurysmal Bone Cyst)

• Unilocular or more commonly, multilocular radiolucency with a ballooned-out appearance due to cortical expansion

Histological Features (Aneurysmal Bone Cyst)

• No epithelial lining; sinusoidal blood spaces are lined by fibroblasts and macrophages (histiocytes)
• Fibrous septa contain multinucleated giant cells; extravasation of RBCs and new bone formation is observed

Differential Diagnosis (Aneurysmal Bone Cyst)

• Mistaken clinically and radiographically for ameloblastoma or odontogenic keratocysts

Treatment (Aneurysmal Bone Cyst)

• Surgical intervention (either conservative or radical); curettage commonly used but recurrence rate is 20-53%

Stafne's Idiopathic Bone Cavity (Static Bone Defect, Latent Bone Cyst)

• An uncommon developmental anomaly of the mandible
• Saucer-shaped depression on the lingual aspect, containing ectopic salivary tissue continuous with the submandibular salivary gland
• Asymptomatic and discovered incidentally on X-rays

Radiographic Features (Stafne's Idiopathic Bone Cavity)

• Round or oval well-demarcated radiolucency between the premolar region and mandible angle; usually beneath the inferior dental canal
• Usually bilateral

Treatment (Stafne's Idiopathic Bone Cavity)

• No treatment needed

Benign Cervical Lymphoepithelial Cyst (Old Name: Branchial Cyst)

• Arise at the lateral aspects of the neck
• Pathogenesis initially thought to be cystic degeneration of epithelium between branchial arches
• More recent theories suggest entrapment of epithelium in cervical lymph nodes with subsequent cystic degeneration

Clinical Features (Benign Cervical Lymphoepithelial Cyst)

• Seen in late childhood or adulthood
• Located at the lateral aspect of the neck, anterior to the sternomastoid muscle
• Potentially infected, with abscess formation and draining sinus

Histological Features (Benign Cervical Lymphoepithelial Cyst)

• Usually lined by stratified squamous epithelium or pseudostratified columnar epithelium
• Underlying connective tissue shows lymphoid aggregates with well-formed germinal centers

Treatment (Benign Cervical Lymphoepithelial Cyst)

• Surgical excision

Dermoid Cyst

• A midline cyst developing between the hyoid bone and mandible
• Pathogenesis involves entrapment of epithelium during incomplete fusion of mandibular and hyoid branchial arches

Clinical Features (Dermoid Cyst)

• Develops at birth
• Midline location with two potential locations (above geniohyoid muscle between it and the oral mucosa; deeply between geniohyoid and mylohyoid muscles leading to submental swelling)
• Size ranges from 2-12 cm; soft, fluctuant, pale yellow swelling
• Potentially doughy consistency if keratin and sebum fill cystic cavity
• Infection can lead to sinus tract opening intraorally

Histological Features (Dermoid Cyst)

• Orthokeratinized stratified squamous epithelium lining
• Skin appendages (sebaceous glands, sweat glands, and hair follicles) present in the supporting fibrous connective tissue wall

Treatment (Dermoid Cyst)

• Surgical removal

Thyroglossal Duct Cyst

• The most common developmental neck cyst
• Midline location
• Pathogenesis involves remnants of the embryonic thyroglossal duct extending from the foramen caecum in the tongue to the thyroid gland location

Clinical Features (Thyroglossal Duct Cyst)

• Two potential locations:
  • Midline in the hyoid bone region (most common); movable swelling that moves with tongue/swallowing
  • In the tongue (lingual thyroid); higher in the duct -Infection can cause drainage through a sinus

Histological Features (Thyroglossal Duct Cyst)

• Above hyoid; lined by stratified squamous epithelium
• Below hyoid; lined by ciliated or columnar epithelium
• Thyroid tissue may be present within the connective tissue wall

Treatment (Thyroglossal Duct Cyst)

• Complete surgical excision
• Confirm functioning thyroid tissue in the neck before lingual thyroid excision

Salivary Gland Cysts (Mucocele)

• Common in minor salivary glands
• Not a true cyst; lacks epithelial lining
• Pathogenesis usually involves mechanical trauma to the excretory duct, leading to mucus extravasation, secondary inflammation and granulation tissue wall formation

Clinical Features (Mucocele)

• Affects the lower lip, buccal mucosa, and floor of the mouth (occasionally tongue and maxillary sinus)
• Usually seen in the second decade
• Superficial swelling; typically < 1 cm
• Seen as bluish submucosal swelling -Possibly history of rupture, collapse and refilling

Histological Features (Mucocele)

• Well-circumscribed cavity filled with mucus surrounded by a thin granulation tissue wall
• Infiltrated large numbers of neutrophils, macrophages, lymphocytes, and plasma cells

Differential Diagnosis (Mucocele)

• Salivary neoplasms, vascular malformations, lipoma, or gingival and eruption cysts

Treatment (Mucocele)

• Surgical excision with removal of the underlying gland to prevent recurrence

Mucous Retention Cyst

• A true cyst; lined by ductal epithelium
• Pathogenesis involves duct obstruction, preventing mucus from escaping

Clinical Features (Mucous Retention Cyst)

• Less common than mucous extravasation type; typically seen in patients over 50 years of age
• Presence in the floor of the mouth, palate, cheek, and maxillary sinus
• Asymptomatic swelling (typically 3-10 mm)
• Mobile, non-tender, and without inflammation

Histological Features (Mucous Retention Cyst)

• Cystic cavity with ductal epithelium lining (usually double layer of columnar or cuboidal cells)
• Mucin within the cavity
• Surrounding connective tissue lacks inflammation

Differential Diagnosis (Mucous Retention Cyst)

• Salivary neoplasms, extravasation mucocele, or connective tissue neoplasms

Treatment (Mucous Retention Cyst)

• Complete removal of the cyst and associated minor salivary gland lobules

Ranula

• An uncommon type of salivary cyst arising from sublingual or submandibular salivary glands
• Mucin spillage from a sublingual gland, sometimes from minor salivary glands in the mouth floor
• Usually unilateral; extending across the entire mouth floor

Clinical Features (Ranula)

• Unilateral or extending to the mouth floor
• Soft, bluish, and fluctuant swelling; typically 2-3 cm diameter
• Painless but may interfere with mastication and speech

Histological Features (Ranula)

• Similar to mucoceles from various locations

Differential Diagnosis (Ranula)

• Dermoid cysts (doughy consistency and midline location)
• Salivary gland tumors or benign mesenchymal tumors

Treatment (Ranula)

• Surgical removal; excision of the involved salivary gland is often performed too.