What is the current management and terminology for odontogenic keratocysts?

Current Terminology and Management of Odontogenic Keratocysts

The current terminology for odontogenic keratocyst (OKC) has reverted back to "odontogenic keratocyst" from "keratocystic odontogenic tumor" according to the latest (4th) edition of the World Health Organization (WHO) Classification of Head and Neck Tumours published in 2017. 1

Terminology Evolution

• Odontogenic keratocysts were reclassified as "keratocystic odontogenic tumours" (KCOT) by the WHO in 2005 to reflect their aggressive and recurrent nature 2, 3
• However, the latest WHO classification (2017) has reclassified these lesions back to "odontogenic keratocysts" (OKCs), considering them as benign cysts of odontogenic origin 1
• OKCs account for approximately 10% of all odontogenic cysts and arise from the dental lamina 1

Clinical Characteristics

• OKCs have a wide age distribution with peak incidence in the third decade of life and a slight male predominance 1
• They typically originate in tooth-bearing regions with the mandible affected more frequently than the maxilla 1
• In the mandible, the most common location is the posterior sextant, angle, or ramus, while in the maxilla, the anterior sextant and third molar region are most commonly affected 1
• OKCs are characterized by aggressive behavior with a relatively high recurrence rate 1
• Multiple OKCs are a major diagnostic criterion for nevoid basal cell carcinoma syndrome (NBCCS), also known as Gorlin syndrome 4, 1

Diagnostic Approaches

• Radiological imaging plays a crucial role in diagnosis and management 1:
  • Panoramic radiography is helpful for preliminary assessment
  • CT is considered the tool of choice for comprehensive evaluation
  • MRI with diffusion-weighted imaging can help differentiate OKCs from other odontogenic lesions
• Histopathological examination is essential for definitive diagnosis, revealing squamous epithelium with focal parakeratosis 5
• OKCs are often misdiagnosed as dentigerous cysts based on clinical and radiographic features alone 2, 5
• Differential diagnoses include ameloblastoma, dentigerous cysts, and radicular cysts 1

Management Approaches

• The primary goal of treatment is to minimize patient morbidity, reduce recurrence risk, and achieve complete surgical removal 5
• Treatment modalities include:
  1. Initial decompression followed by aggressive curettage and peripheral ostectomy with methylene blue staining - this approach has shown success with up to 6 years of follow-up 6
  2. Enucleation - though this may be insufficient as a standalone treatment due to high recurrence rates 5, 3
  3. Marsupialization followed by secondary enucleation 3
  4. Resection for extensive or recurrent lesions 3

Association with Syndromes

• OKCs are a common feature in nevoid basal cell carcinoma syndrome (NBCCS), also known as Gorlin syndrome 4
• In NBCCS, OKCs are associated with PTCH1 gene mutations but are not typically seen in patients with SUFU mutations 4
• Patients with NBCCS-associated OKCs require careful management, especially regarding radiation exposure, as they are prone to developing basal cell carcinomas and other tumors 4
• For patients with NBCCS, avoidance of ionizing radiation is recommended unless absolutely necessary 4

Follow-up Recommendations

• Regular and long-term follow-up is essential due to the high recurrence rate 5, 3
• Follow-up should include clinical examination and appropriate imaging (CT or MRI) 1
• The recurrence rate varies depending on the treatment modality, with more conservative approaches generally associated with higher recurrence rates 3
• Follow-up periods of at least 5 years are recommended to monitor for recurrence 6, 5

Important Considerations and Pitfalls

• Misdiagnosis is common - OKCs are frequently mistaken for dentigerous cysts or other odontogenic lesions 2, 5
• Incomplete removal is a major cause of recurrence due to the thin, friable nature of the cyst lining 3
• Multiple OKCs should prompt investigation for NBCCS 4, 1
• Treatment should be more aggressive for recurrent lesions or those associated with NBCCS 3