Management of Odontogenic Cysts & Tumors

origins of odontogenic cysts/tumors

-residual tooth-forming tissue is source

source tissue, where it sits, what it can become

cyst v. tumor

-cyst: epithelium-lined cavity with fluid or keratin, grows by internal pressure and pushing bone ahead of it, usually separates cleanly from bone, shrinks when drained → enucleation or decompression

-tumor: true neoplasm with autonomous growth, infiltrative types extend into marrow beyond the visible edge, encapsulated types shell out, draining does not cure it → enucleation (encapsulated) or resection with margins (infiltrative)

classification of cysts, benign tumors, malignant

describing the lesion- locularity, relation to teeth, borders, neighbors, contents

pericoronal differential

-dentigerous cyst

-OKC

-unicystic ameloblastoma

-AOT (anterior, canine)

-ameloblastic fibroma

-CEOT, COC

periapical/lateral root differential

-PAR/radicular cyst

-lateral periodontal cyst

-early COD

-cementoblastoma

-traumatic bone cyst

multilocular differential

-OKC

-ameloblastoma

-myxoma

-CGCG

-AV malformation

-aneurysmal bone cyst

-intraosseous carcinoma

multifocal differential

-NBCCS (multiple OKCs)

-cherubism

-langerhans cell histiocytosis

-hyperparathyroidism (brown tumors)

-early COD

-multiple myeloma

multilocular radiolucency? think…

MACHO

-myxoma: young adults; straight “tennis racket” septa

-ameloblastoma: 30-70; posterior mandible; soap bubble/honeycomb appearance

-central giant cell granuloma: younger; anterior mandible

-hemangioma: vascular lesion

-OKC: 2nd-3rd decade; little expansion

treatment for MACHO differential

aspirate returns, think, next

treatment ladder

-decompression/marsupialization (shrink it first, drain placement following incisional biopsy)

-enucleation with/without curettage

-enucleation + adjunct (peripheral ostectomy, Carnoy’s 5-FU, cryotherapy)

-marginal resection (inferior border kept; continuity preserved)

-segmental resection + reconstruction (continuity defect; bone graft or free flap), for infiltrative lesions

-up the ladder: more morbidity, lower recurrence; pick the rung by diagnosis, size, location, age, nearby vital structures, recurrence risk, the patient

traumatic bone cyst treatment

-exploring it is the treatment

decompression

-lesion shrinks, bone backfills

-cyst wall thickens, so later enucleation is easier

-lining histology changes

-choose when large lesion near the IAN, sinus, or roots, child with developing teeth that may still erupt, patient who can’t tolerate a large surgery

-considerations: months of irrigation, compliance matters, usually a second surgery to enucleate

-biopsy before or at drain placement, while the lining is still diagnostic

dentigerous cyst

-about 1/3 of odontogenic cysts

-fluid between the reduced enamel epithelium and the crown; attached at the CEJ

-most often: mandibular 3rd molar > maxillary canine > maxillary 3rd molar > mandibular 2nd premolar

-central (most common), lateral, or circumferential

-unilocular and corticated; can push a tooth far from its site and resorb roots

-a pericoronal (follicular) space wider than about 3-5mm on radiograph is the conventional threshold that should raise suspicion for a dentigerous cyst rather than a normal dental follicle

-treatment: small- enucleation with the tooth; large- marsupialization, then enucleation once it has decompressed; recurrence is uncommon, always send to pathology

cyst, key features, treatment: radicular, residual, lateral periodontal, glandular, calcifying (Gorlin)

the most common radiolucency at a root apex

-periapical lesion of endodontic origin

-test vitality before anything else

-non-vital tooth: treat the tooth first

-persists after endo: biopsy (+ apicoectomy)

-vital tooth: think beyond endo

OKC

-cyst that behaves like a tumor

-2nd-3rd decade; slight male predilection

-posterior mandible (3rd molar/ramus) most common

-from dental lamina rests; PTCH tumor-suppressor gene

-tunnels through marrow with little expansion; displaces the IAN, resorbs roots

-thin, friable lining → hard to remove in one piece

-recurs, mostly within 5 years

nevoid basal cell carcinoma syndrome (Gorlin)

-multiple OKCs (~90%)

-multiple basal cell carcinomas (~90%), can start in childhood

-palmar and plantar pits

-calcified falx cerebri

-bifid or fused ribs, spina bifida

-frontal bossing, macrocephaly, hypertelorism

-medulloblastoma, ovarian fibromas

-cleft lip/palate (~5%)

-genetics: autosomal dominant, PTCH1 (9q22.3) in most, also PTCH2/SUFU, hedgehog signaling pathway, ~40% arise de novo, ~1 in 57,000 (estimates vary)

-care: lifelong jaw surveillance, dermatology for skin cancer checks, genetics referral (screen the family), avoid radiotherapy, minimize ionizing radiation

OKC recurrence rates with treatment options

OKC- adjuncts for bone cavity, how it works, watch out for

treatment of biopsy-proven OKC based on size/aggressiveness

-small, accessible: enucleation + peripheral ostectomy + adjunct (5-FU or Carnoy’s)

-large, near IAN or teeth, child: decompress first, then enucleate + adjunct once smaller

-repeated recurrence, aggressive: resection with ~1cm margins

-for everyone: radiographic follow-up for at least 5 years- most recurrences show up by then, NBCCS: lifelong

ameloblastoma

-most common clinically significant epithelial odontogenic tumor

-age 30-70; mandibular molar/ramus

-slow, painless expansion

-uni- or multilocular: “soap bubble” (large locules), “honeycomb” (small)

-root resorption; can mimic a dentigerous cyst

-variants: conventional, unicystic, peripheral, malignant

pattern and histology of ameloblastoma- follicular, plexiform, acanthomatous, granular cell, desmoplastic

why we resect a benign tumor

-70-85% recur after enculeation and curettage, usually within 5 years; palliative only

-1.0-1.5cm bony margins plus one uninvolved anatomic barrier: curative marginal or segmental resection

unicystic ameloblastoma

-type drives management

-13-21% of ameloblastomas, younger pts, mandibular 3rd molar, looks like a dentigerous cyst

ameloblastoma- less common variants (variant, behavior, treatment)

odontogenic myxoma

-ages ~10-40, mean ~30

-no sex predilection

-mandible more often than maxilla

-from odontogenic ectomesenchyme; gelatinous, with no capsule

-film: multilocular, thin straight “tennis racket” septa; soap bubble or honeycomb

-histology: loose myxoid stroma with spindle- and stellate-shaped cells

-treatment: resection, 1.0-1.5cm margins + one uninvolved anatomic margin, curettage only for small lesions or palliation, no capsule: curettage leaves tumor in marrow

central giant cell granuloma

-peak ages 5-15; female 2:1

-anterior mandible; uni-or multilocular

-same histology as a brown tumor: rule out hyperparathyroidism when the picture fits

-aggressive if: 1 major (>5cm or recurrence) or 3 minor (rapid growth, tooth displacement or loosening, cortical thinning or perforation, root resorption)

-treatment: enculeation + peripheral ostectomy (~20% recurrence), recurrent- resection, 1cm margins; large- intralesional steroids, weekly x6 weeks, other adjunct medications

cherubism

-child

-bilateral

-symmetric multilocular jaws

-autosomal dominant

-regresses after puberty, observe

AV malformation

-any multilocular lesion could be one

-aspirate first: bleeding can be fatal

COD

-vital teeth

-predominantly seen in black women

-4th-5th decade

-early lesions radiolucent

-don’t biopsy or extract- risk of osteomyelitis

nasopalatine duct cyst

-midline anterior maxilla

-vital incisors

-non-odontogenic

-enucleation

tumors that don’t require margins

tumors that need margins