What Is Gorlin Cyst?
A Gorlin cyst or calcifying odontogenic cyst is a cyst of dental origin. This is a rare developmental lesion of an odontogenic origin first documented by Gorlin et al. in 1962, hence the name. Later in 2005, WHO (World Health Organization) named this cyst a calcifying cystic odontogenic tumor (CCOT) after assessing its histological complexity, types, aggressiveness, or proliferative capacity to spread to the surrounding tissues locally.
Although the clinical features of this cyst are benign, as a pathologic entity, the lesion or cystic contents encompass a wide range of clinical behavior that varies from individual to individual. This cystic lesion exhibits a spectrum of histopathological patterns: cystic, solid, and aggressive. Considering the variable histopathological patterns and aggressive biological behavior, Gorlin's cyst was reclassified as an odontogenic tumor (neoplasm) in the 2005 WHO classification. The term calcifying odontogenic cyst and calcifying odontogenic tumor have been used interchangeably though the topic still remains debatable.
Several authors have attempted to classify the Gorlin cyst based on the histopathological types. They have renamed this entity calcifying ghost cell odontogenic cyst or dentinogenic ghost cell tumor, though the most commonly used terminology is CCOT.
What Are the Clinical Types of Gorlin Cyst?
The lesion or cyst clinically manifests either as
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Central variant (intraosseous).
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Peripheral variant (extraosseous).
Out of these variants, the central variant of the Gorlin cyst is more prevalent or often observed in clinical expression. Research shows that these cysts occur over a broad spectrum of age, from the first decade of life to the eighth decade of life. However, more cases were reported in the second decade of life in young adults, and the mean age group was between 20 - 30 years. This cyst affects both genders equally and also without any distinct racial predilection.
Gorlin cyst represents up to nearly 2 % of all oral or odontogenic pathologies of the jaw bones. The characteristic clinical features of this cyst are -
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It is a painless and slow-growing lesion that may equally affect the upper (maxilla) and lower (mandible) jaw bone.
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The origin of the cyst tends to be intraosseous or within the bone though extraosseous cysts can also occur.
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The anterior segment of the maxilla or mandible tends to be a common location for cyst occurrence.
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Teeth associated with the Gorlin cyst are commonly known to be affected by root resorption and divergence that can be detected radiographically by IOPA X-rays (intraoral periapical radiographs), and OPG (orthopantomogram), or CBCT (cone-beam computed tomography systems - 2D or 3D imaging radiographic dental modalities).
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In most cases, this cyst is also found to be associated with an impacted tooth that can predictably occur in up to one-third of Gorlin cyst cases.
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Asymptomatic swelling within the upper or lower jaw bone, most often anteriorly, is a common clinical feature with the expansion of buccal or lingual cortical plates.
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In both extraosseous and intraosseous lesions, the expansion of the buccal or lingual cortical plates is a confirmatory diagnosis when the cystic content and lesion are benign.
How Is Gorlin Cyst Diagnosed?
Radiographic Diagnosis -
Radiographically Gorlin cyst appears mainly as a unilocular or multilocular radiolucent mass or cystic lesion. This can either be well-circumscribed or poorly-defined margins. When observed in association with unerupted teeth, the dentist should consider the differential diagnosis of other odontogenic lesions even though it is still possible for a Gorlin cyst to be associated with unerupted teeth. Calcification or calcified cystic regions is an important and confirmatory radiographic diagnosis for the Gorlin cyst in nearly half of the reported or observed cyst cases in affected individuals.
Histopathologic Diagnosis -
The unique histopathological features of the Gorlin cyst include the components of a fibrous wall with the cyst lined by odontogenic epithelium that is composed of cells that resemble ameloblast-like cells (tall columnar). Stellate reticulum-like cells usually overlie the basal cell layer with the ghost cells, hence the name dentinogenic ghost cell tumor. It may also show signs of calcification.
What Are the Treatment Strategies for Gorlin Cyst?
The treatment of choice for the Gorlin cyst is always a conservative surgical approach with a broad base enucleation that would prevent recurrence in case of intraosseous lesions of the cyst. Surgical excision is preferred for the extraosseous form of the Gorlin cyst and the long-term prognosis is excellent as the recurrence rates for this type are extremely low. Even though intraosseous Gorlin cysts have seemingly high recurrence rates, the prognosis and survival rate are positively better. Follow up visits help in tracking the development of recurrent lesions, if any.
Conclusion:
Thus, the Gorlin cyst is a challenging entity presenting as a cyst or benign tumor with probable malignant potential and also in association with other lesions of odontogenic origin. However, prompt diagnosis and timely surgical resection of the cyst results in an excellent long-term prognosis. Surgical elimination of the cystic entity followed by periodic assessment of the surgical site is often advised to rule out the possibilities for reoccurrences.
