Introduction
While most ameloblastoma lesions are benign, cancerous and aggressive lesions often have an intracranial counterpart. Read the article to understand the possibility, features, and clinical management of AMBL tumors with intracranial complications or spread, shed light on the intricacies of diagnosis and treatment in such cases, and explore potential advancements in therapeutic approaches. This comprehensive review aims to provide valuable insights into optimizing patient outcomes and guiding future research efforts in the field of AMBL management.
What Is the Possibility of Ameloblastoma Tumors Having an Intracranial Spread?
Ameloblastoma (AMBL) is an odontogenic tumor (tooth-related tumor formation) typically considered benign, yet its aggressive behavior poses a challenge due to high recurrence rates. Aggressive or untreated growth can lead to intracranial spread. According to the World Health Organization's global medical report, ameloblastoma is classified as either benign (non-cancerous and localized) or malignant (with metastatic potential). In cases of invasive AMBL tumors with neurologic or brain involvement, life-threatening complications such as intracranial hypertension (increased pressure inside the skull) and severe neurological deficits may arise, impacting survival rates and potentially leading to patient demise.
Research, exemplified by Olaitan et al.'s study of 315 AMBL patients, indicates that less than one percent of cases exhibit intracranial manifestations. Although rare, intracranial involvement of AMBL is documented in dental literature, often necessitating extensive surgical intervention and interdisciplinary management involving both neurosurgeons and maxillofacial surgeons. This underscores the critical importance of early detection and comprehensive treatment planning to mitigate the potentially devastating consequences of intracranial AMBL involvement.
What Factors Contribute to the Variability, Incidence, and Types?
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Higher incidences of malignant tumors of AMBL with the possibility for intracranial complications or spread are more commonly found in regions of Africa, China, and India, as per documented case reports. However, dental research indicates no specific geographic epidemiological variations, nor do these malignant AMBL cancers demonstrate predilections for population groups based on sex, race, or age. According to case reports, the median age of malignant AMBL diagnosis with intracranial manifestations typically falls between the second and third decades of life, ranging from 24 to 38 years.
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AMBL aggressive lesions exhibit a locally aggressive growth pattern, often involving various structures of the skull or facial skeleton. They can spread to the base of the skull, paranasal sinuses, infratemporal fossa, pterygopalatine fossa, parapharyngeal (deep tissues of the neck that contain mostly fat as well as blood vessels) space, or even to the orbit. About two percent of benign tumors may evolve into malignant forms when left untreated.
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The variability of the lesions is dependent on their type or cell pattern, as outlined below, and mainly on the tumor's biological behavior. Based on the anatomical classification provided by the WHO (World Health Organisation), considering primary factors such as the tumor's location and histopathology, benign ameloblastomas (tumors of the jaw) are further classified into the following four subtypes:
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Peripheral or extraosseous variants of ameloblastoma.
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Solid or multicystic variant of ameloblastoma.
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Unicystic variant of ameloblastoma.
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Desmoplastic variant of ameloblastoma.
Only two percent of all benign AMBL tumors are known to have the potential for malignant or cancerous transformation. Malignant ameloblastomas or tumors, though considered rare or less common in dental research or literature, are complexities that exhibit the potential for recurrence and intracranial manifestations or involvement. Malignant AMBL tumors are further subclassified into:
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Primary ameloblastic carcinoma.
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Secondary intraosseous ameloblastic carcinoma.
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Secondary peripheral ameloblastic carcinoma.
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Metastasizing ameloblastoma.
What Is the Management of AMBL?
However, these studies also highlight that approximately ten percent of patients suffering from malignant AMBL tumors would have some form of neurological or cerebral or brain involvement, with a direct extension into the brain. These cases are eventually accompanied by a higher risk of mortality rates, with a very poor prognosis despite extensive radical surgery and adjunct treatment.
According to information available in dental literature, radical surgery is the gold standard treatment modality to achieve the best surgical outcomes, with maxillofacial surgeons usually recommending adequate surgical margins when resecting the tumor. En-bloc tumor resection of these AMBL tumors with wide bone margins, followed by maxillofacial surgeons employing either immediate or delayed bone reconstruction of surgical defects in the face or lower jaw, is the main treatment modality of choice. Facial reconstruction is the most important post-surgical intervention, utilizing a combination of tissue grafts and prosthetic facial and dental rehabilitation. In tumors that are aggressive and extensive, the cells may extend or involve the intracranial compartments, leading to serious life-threatening consequences and significantly increased mortality rates.
To prevent further intracranial complications in such tumors and to promote a significant increase in survival rates for these cancer patients, an interdisciplinary management strategy is advocated.
Does the Follicular Pattern AMBL Show Intracranial Involvement?
Among the variants, the multicystic or solid variant is the most common type of ameloblastoma, accounting for more than 90 percent of all slow-growing benign jaw tumors, according to medical research and literature. These benign jaw tumors, known as benign ameloblastomas, commonly exhibit either a follicular pattern or a plexiform type pattern when observed histopathologically.
In some cases of multicystic ameloblastoma tumors, it is not uncommon to observe both follicular and plexiform patterns simultaneously. Several subtypes may further exist histologically for this major multicystic variant, such as acanthamatous, basal cell, clear cell cystic, granular, spindle cell, etc. Therefore, histopathological diagnosis of ameloblastoma tumors may be an important factor in treatment planning. Malignant or cancerous ameloblastoma tumors occurring in the maxillary or upper jaw region with a follicular histological variant hold significant clinical value because these follicular ameloblastomas may have the potential for intracranial spread and complications.
Incomplete surgical resection of malignant tumors may often pose postoperative complications, including tumor recurrence. In follicular variants of multicystic ameloblastoma tumors, cerebral involvement may be extremely common and pose life-threatening consequences.
Conclusion
The main risk associated with aggressive AMBL tumors lies in their potential invasiveness and high local recurrence rates. Therefore, timely diagnosis and interdisciplinary management by oral and maxillofacial surgeons, oncologists, and neurologists in cases of ameloblastomas with intracranial involvement are crucial factors in improving prognosis and survival rates for affected patients. Collaborative efforts among these specialists ensure comprehensive treatment approaches tailored to each patient's unique condition, aiming to minimize the risk of complications and optimize long-term outcomes.
