Keratocystic Odontogenic Tumor (Odontogenic Keratocyst) in BCCNS

June 14, 2019

Nolan A. Jenkins, DDS

Background

• Born in Holt, Michigan

• Undergraduate: University of Tulsa (Tulsa, OK)

• Dental School: University of Oklahoma College of Dentistry (Oklahoma City, OK)

• Oral & Maxillofacial Surgery Internship and Residency:

Carle Foundation Hospital (Champaign-Urbana, IL)

• Current practice: Midtown Oral & Maxillofacial Surgery in Austin, TX

• Affiliations with Dell Children’s Medical Center, Dell Seton Medical Center UT, and Seton Medical Center Austin

Midtown Oral & Maxillofacial Surgery / Austin, TX

Disclosures

I have no disclosures to reveal.

Diagnosis, Treatment, and Surgery

What is a cyst?

A cyst is a pathologic cavity with an epithelial lining (lined by cells) that is filled with a fluid or semi-solid substance

Terminology

• “Keratocyst” or “Keratocystic” refers to a cyst that produces keratin

• “Odontogenic” - Develops from cells that usually develop teeth

What makes a KOT (OKC) unique?

• Distinct microscopic structure and clinical behavior

• Greater growth potential than other cysts

Nomenclature: KOT or OKC?

• There is some controversy regarding the naming and classification of this entity

• In 2005, the World Health Organization renamed this entity from Odontogenic Keratocyst (OKC) to Keratocystic Odontogenic Tumor (KOT)

Nomenclature: KOT or OKC?

• In 2017, the W.H.O. reversed this decision, renaming the entity an OdontogenicKeratocyst

• Currently, both terms are used, and the term used is based upon the practitioner’s preference

• For the purposes of this talk, we will use KOT for consistency – just know you’ll hear both!

Characteristics of Keratocystic Odontogenic Tumors

(KOTs)

• 60% develop between ages of 10-40

• Slight male predilection

• Small cysts are are often asymptomatic

• Larger cysts may present with jaw swelling or pain

• Advanced: Mobile teeth, difficulty opening mouth, facial asymmetry

• Tend to grow in an anterior-posterior direction (back to front)

• Do NOT invade nerves (typically do not cause numbness)

Keratocystic Odontogenic Tumors (KOTs)

• Occur in both the upper and lower jaw

– 60-80% reported in the lower jaw (mandible)

– More often in the wisdom tooth areas

Keratocystic Odontogenic Tumors (KOTs)

• Can be single or multiple

–Multiple KOTs common in BCCNS

• BENIGN cyst

–Prognosis for almost all KOTs = Good

– If detected early and closely monitored, rare to become very aggressive

–Propensity to transform into a true tumor is very rare and no greater than with other type of benign jaw cyst

Keratocystic Odontogenic Tumors (KOTs)

• Recurrence rate: Wide range reported in studies on the general patient population (5-50%)

– In reports that include a large number of cases, typically reported around 30%

– Higher in the lower jaw, particularly in wisdom tooth areas

– For BCCNS, recurrence is known to be higher -reported as up to 82%

Where do they come from?

• KOTs arise from rests of dental lamina

(left over cells involved in tooth development)

• Molecular/genetic alterations:– Greater expression of PCNA, Ki-67

– (compared to other cyts)

– In BCCNS, > 85% PTCH1 mutation

– Loss of heterozygosity for genes:• p16, p53, MCC, TSLC1, LATS2, FHIT

Do KOTs affect your teeth?

• Up to 40% of KOTs are associated with an uperupted(“impacted”) tooth – can be more common in individuals with BCCNS

• Resorption (damage to tooth roots) is less common than with other pathological processes

• Teeth may become loose or displaced with larger or more aggressive cysts, as bone is resorbed or displaced

Implications for BCCNS

• KOTs occur in up to 90% of individuals with BCCNS

• Tend to occur at a younger age

– Usually earlier than basal cell carcinomas on skin

– Treatment usually begins before the age of 19

• Higher rate of recurrence (some report up to 82%)

• Infection of cysts is more common than in the general population

Implications for BCCNS

• Potential for more aggressive lesions

– Possibly attributed to molecular and genetic factors

• Overexpression of p53, Cyclin D1 (bcl-1) oncoproteins

• Cysts are frequently multiple

– 1/3 of patients have a single cyst at time of presentation, but develop additional cysts later

• Tend to be associated with impacted teeth

• Routine monitoring and management are important, given the propensity to develop them

Diagnosis – How do we find them?

• Most times, these are discovered by your dentist using routine dental x-rays

– For BCCNS patients, routine dental check-ups are a must

• Patients who have previously been diagnosed and treated for KOTs should be followed regularly by your oral surgeon

– Recurrences are common, but may occur gradually

• Larger KOTs may cause symptoms: Facial asymmetry, jaw swelling, trismus, pain, mobile teeth

Diagnosis

• Referral to an oral and maxillofacial surgeon (or head/neck ENT surgeon) is indicated if suspicious of cysts

• Definitive diagnosis requires biopsy

– Histology is pathognomonic (or very distinct for this entity)

– Clinical and radiographic appearance can mimic other lesions

Diagnosis: Histology

• Stratified squamous epithelium 6-8 cells thick

– Parakeratotic luminal cells

– Palisaded basal cell layer of hyperchromatic cuboidal/columnar cells

• Thin friable fibrous wall

• Satellite cysts (“daughter cysts”) project into fibrous wall

• Clear or “cheesy” fluid caused by production of keratin

Diagnosis

• Additional imaging studies your surgeon may order to help in managing KOTs:

– Panoramic X-ray (“Panorex”)

– Cone-beam (In-office) CT scan

– Medical CT scan

• Note: MRIs are not routinely ordered

Dental X-rays

Dental X-rays

Panoramic X-Ray (Panorex)

Panoramic X-Ray (Panorex)

Panoramic X-Ray (Panorex)

CT Imaging

Treatment of KOTs

• There are multiple ways to manage KOTs– Enucleation and curettage (E & C)

• E & C plus Chemoablation or Cryoablation

• E & C plus Peripheral Ostectomy

• E & C with Peripheral Ostectomy AND Chemoablationor Cryotherapy

– Decompression

– Marsupialization

– Marsupialization followed by Enucleation

– Resection: En block or segmental

Treatment of KOTs (cont.)

• KOTs do not invade nerves

– Nerves can be separated and salvaged

Chemical cautery – Carnoy’s Solution

• Can be used to treat the bone following enucleation/curettage, as a tissue fixative (caustic to living cells)

• Original formula (“Carnoy’s CS”): 60% Ethanol, 30% Chloroform, 10% Glacial acetic acid, with 1g ferric chloride– In 2013, the FDA banned the use of chloroform for

compounding solutions

• Modified Carnoy’s solution (“Carnoy’s MC”) that does not contain chloroform is still used by surgeons for the same purpose

Decompression / Marsupialization

Notice the cyst shrank, and the impacted tooth has drifted into a more favorable position

Surgical management of Teeth

• Conservative approach – keep as many teeth as possible!

• Some impacted teeth can be guided into position with marsupialization and orthodontics

• Remove as much of the cyst as possible from tooth roots

– Potential compromise between maintaining dentition and potential for recurrence

Surgical management of Teeth

• Bone remodels and/or fills in gradually after cyst removal – loose teeth may stabilize

• Affected teeth DO NOT typically need root canal therapy

– Teeth are denervated but NOT deviatalized

• May be reasonable to remove wisdom teeth earlier

Lifelong concerns & Follow-up

Postoperative Monitoring

• REMEMBER: Recurrence of KOTs and multiple independent KOTs in BCCNS are COMMON

• KOTs tend to recur or appear with variable timeframes –Can be years following initial treatment

• A strict recall schedule is important!

• Recall visits with your surgeon every 6-12 months recommended– This typically involves an exam and repeat imaging in order to

evaluate healing and detect interval changes in bone

Postoperative Monitoring

• Once there is evidence that there have been no recurrences or new KOTs for several years, it may be reasonable to progress to annual visits (minimum 5 years)

• Routine dental check-ups are equally important

– Impacted teeth

– Malpositioned teeth

– Orthodontic concerns

– Effects on nearby teeth

• Orthodontic care may be crucial, particularly when surgery is taken on at an early age

– Maintain the health of the teeth

– Improve or maintain an appropriate bite (occlusion)

– Maintain spaces where teeth have been lost, in order to allow for rehabilitation of function and aesthetics

• Recurrence of KOTs in BCCNS is common

Questions/Comments?

Citations

Neville, Brad W., et al. “Odontogenic Keratocyst (KeratocysticOdontogenic Tumor).” Oral and Maxillofacial Pathology, 4th ed., Elsevier Saunders, 2016, pp. 636–644.

Marx, Robert E., and Diane Stern. “OdontogenicKeratocyst/Basal Cell Nevus Syndrome.” Oral and Maxillofacial Pathology: a Rationale for Diagnosis and Treatment, 2nd ed., II, Quintessence Publishing Co Inc., 2012, pp. 616–636.

Pogrel, M. A. “Keratocystic Odontogenic Tumor.” Current Therapy in Oral and Maxillofacial Surgery, Elsevier Saunders, 2012, pp. 380–383.

THANK YOU!