Non-Odontogenic Tumors of the Jaws

What is Non-Odontogenic Tumors of the Jaws?

Non-odontogenic tumors of the jaw encapsulate a broad variety of illnesses that are beyond the scope of this comprehensive summary. However, we will concentrate on some of these illnesses that you might come across more frequently in a clinical setting, even though they’re quite rare. Six specific tumors: osteosarcoma, fibrous dysplasia, central giant cell granuloma, osteoma, osteochondroma, and osteoblastoma, will be examined in greater detail. Here is a more extensive breakdown of non-odontogenic tumors of the jaw, grouped by the source tissue, to give you a sense of the topic’s breadth.

Bone tumors can be classified as benign (not harmful) or malignant (cancerous). Examples of benign bone tumors include osteoma, osteoblastoma, osteoid osteoma, ossifying fibroma, chondroma, chondroblastoma, and chondromyxoid fibroma. Malignant bone tumors include osteosarcoma, Ewing’s sarcoma, chondrosarcoma, and metastases.

Tumors can also derive from fibroconnective or fibro-osseous tissue, fat, muscle, blood vessels, nerves, or result from certain blood diseases. Examples of benign fibroconnective or fibro-osseous tumors include fibrous dysplasia, cherubism, non-ossifying fibroma, and desmoplastic fibroma. Fibrosarcoma is a malignant example.

Osteosarcoma, a malignant tumor of the bone, accounts for over half of all bone tumors. Osteosarcomas of the jaw make up 6% of all osteosarcomas, and are the second most common kind of cancer in the jaw. They can either originate from a healthy bone (primary) or an already diseased bone or benign tumor (secondary). These tumors are graded and classified based on their histological features, which means what they look like under a microscope.

Fibrous dysplasia is a rare genetic illness that leads to abnormal bone development and transformation. It does not result in distinct lesions, but it does lead to abnormal bone growth, contributing to its classification as a non-odontogenic tumor. It most often affects the jaws, particularly the maxilla, leading to significant asymmetry, deformity, and, if it occurs around the eye socket, blindness.

Central giant cell granuloma is the most frequently encountered non-odontogenic tumor in the jaws, comprising 7% of benign jaw tumors. This tumor is benign, but it can be locally destructive. They are most commonly found in the front part of the lower jaw but can affect the upper jaw. The tumor leads to the enlargement of lytic lesions, which are areas where tissue is being destroyed.

An osteoma is a benign, slow-growing growth of compact or cancellous bone. These most often appear in the face and head bones, especially in the paranasal sinuses. They can occur in three types: central (arising from the endosteum), peripheral (arising from the periosteum), and extraskeletal (originating from soft tissues, specifically muscles).

Osteochondroma, osteoblastoma, and several other diseases are also important tumors that could be found during a checkup. Understanding these terms can help you better communicate with your healthcare professional and make informed decisions about your health.

What Causes Non-Odontogenic Tumors of the Jaws?

Osteosarcoma

The exact cause of osteosarcoma, a type of bone cancer, is undetermined. A lot of research focuses on osteosarcoma in long bones rather than in jaws. Osteosarcoma in the jaw tends to occur later in life, is usually not as serious, is less likely to spread to other parts of the body, and has a better prognosis.

There’s a hypothesis that defects in two specific genes (p53 and RB1) can contribute to the development of this disease. Furthermore, people with rapid bone growth or conditions such as Paget disease are thought to have an increased risk. Some environmental factors, such as ionizing radiation and chromic oxide exposure, can also increase the risk of osteosarcoma.

Fibrous Dysplasia

Fibrous dysplasia, a bone disorder where normal bone is replaced with fibrous bone tissue, is caused by a genetic mutation in a gene called GNAS 1. This mutation interferes with normal bone maturation during the embryonic stage of development and can happen at different times for each individual, leading to variations in how the disease manifests. If the mutation occurs early, it can lead to conditions like McCune-Albright syndrome, whereas a later mutation might lead to a milder form of the disease.

Central Giant Cell Granuloma

Central giant cell granuloma, a benign lesion typically of the jaw, was once believed to be a response to trauma or inflammation within the bone marrow. However, this theory is no longer widely accepted. Instead, most experts believe they occur due to changes in the normal functions of cells, possibly related to disrupted cell cycle regulation.

Osteoma

The cause of osteoma, a type of benign bone tumor, is unknown. Some believe they are developmental abnormalities, others think they could be due to abnormal cell growth, or a response to trauma or infection that results in uncontrolled bone growth. The theory that trauma or infection might be involved is supported by the fact that osteomas often develop near the areas where muscles attach to the lower part of the jawbone.

Osteochondroma

There are various theories about the development of osteochondromas, which are noncancerous bone growths. Some believe they develop due to a herniation or bulging of the cartilage at the ends of the bones. Others suggest that stress on the periosteum, the membrane that covers bones, could trigger these growths. The most commonly accepted theory is that cells within the periosteum undergo changes and form cartilage and then bone.

Osteoblastoma

The cause of osteoblastomas, a rare bone tumor, is not well understood. Some believe that trauma and an unusual response to injury might contribute to their development, but more research is needed to confirm these theories.

Risk Factors and Frequency for Non-Odontogenic Tumors of the Jaws

• Osteosarcoma typically appears in the jaw later than in long bones, commonly in the third or fourth decade of life. Both males and females are equally affected. However, jaw osteosarcoma only accounts for 6% of all osteosarcomas.
• Fibrous dysplasia is rare, usually seen in young people, with few cases reported after the age of 20. This disease has no preference for any gender.
• Central giant cell granuloma incidence is 0.0001% in the population. It usually develops between the ages of 5 and 15, barely appearing after 30 years of age. It’s more common in females, with a 2:1 female to male ratio.
• Jaw osteoma is rare, with an incidence of 0.01 to 0.04%. No particular age group gets it more than others. Some research suggests there could be a slight predominance in males, but this isn’t strongly supported by the medical literature.
• Osteochondroma can happen at any age but more commonly over 20 years old. Compared to long bone osteochondromas, those in the facial skeleton appear at older ages, usually between 20 and 40 years. Males are more affected, with a 2:1 male to female ratio.
• Osteoblastoma of the jaw often appears in males more than females, with a 6:4 male to female ratio. It can occur in any age from 5 to 60 years. The most common age of onset is 20 years, with the more aggressive type often seen in teenagers or young adults.

Signs and Symptoms of Non-Odontogenic Tumors of the Jaws

Osteosarcomas, often found in the jaw, usually show themselves as a swelling instead of causing pain as they might in other parts of the body. Patients may also experience numbness, loose teeth, and blocked noses, but often confuse these symptoms with side effects from recent dental work. This misunderstanding can lead to a delayed diagnosis of osteosarcoma.

Fibrous Dysplasia generally appears in children and teenagers as a painless, uneven growth of bone. The condition is usually most active during periods of rapid growth and tends to slow down as the patient matures. The effects of fibrous dysplasia can vary depending on which bones are affected. It can lead to malocclusion (misaligned teeth), and could even result in blindness if it impacts certain cranial bones.

Central Giant Cell Granuloma can be mild, manifesting as a painless enlargement of bone. When aggressive, it can lead to painful swelling, displacement of teeth, and affects the alveolar ridge (the jaw area where teeth are anchored). Sometimes, a blue or brown discoloration can appear in the mouth due to thinning of the bone and overlying tissue. This enlargement usually happens within a period of two weeks to a few months.

Osteomas are slow-growing lesions that can be unnoticed for many years and may even be found accidentally during imaging procedures. Depending on their location and size, they can distort normal structures and functions, potential causing difficulty in opening the mouth, malocclusion, occasional pain, and changes in facial symmetry and appearance.

Osteochondromas commonly occur in the lower jaw (mandibular condyle) or the bone process near the mouth (coronoid process), and are often associated with issues related to the jaw joint (TMJ). Symptoms include changes in bite, facial asymmetry, and problems in opening the mouth (trismus). In some cases, these lesions could influence hearing by causing canal stenosis (narrowing) or even hearing loss. Generally, the clinical symptoms are milder than anticipated due to their slow growth.

Patients with osteoblastoma often show minimal symptoms, but they may notice a swelling accompanied by dull, intermittent pain as the bone expands. The symptoms may be experienced over months or years. Aggressive osteoblastoma primarily affects young individuals. Its rapid growth and larger size may result from increased bone cell activity in children and young adults, which can lead to local destruction and high recurrence rates.

Testing for Non-Odontogenic Tumors of the Jaws

For Osteosarcoma, simple X-rays help doctors identify changes in the bone. They might see a lesion (an area of damaged tissue) with irregular borders. Sometimes, the tumor causes a “sun-ray” pattern or a “Codman’s triangle,” where it looks like the tumor elevates the bone’s outer layer. But these signs are not always present and not unique to osteosarcoma.

A more precise image of the bone is acquired through Magnetic Resonance Imaging (MRI). This helps doctors see how far the disease has spread, especially its effect on the bone marrow and surrounding structures. To confirm osteosarcoma, a biopsy (taking a small sample of tissue for lab testing) is essential. Sometimes the biopsy may need to be repeated to get a correct diagnosis. Doctors also do CT scans (computerized tomography – a type of X-ray that gives a more detailed picture) of the chest to see if the disease has spread to the lungs.

Fibrous Dysplasia shows up on X-rays as a lesion that blends into the surrounding bone and looks like ground glass. Over time, this area may become more dense. CT imaging shows that the tumor causes expansion and thinning of the bone. It may also move the canal that carries a nerve in the lower jaw and cause tooth loss.

To diagnose Central Giant Cell Granuloma, doctors need to rule out other conditions. For example, a rare condition called hyperparathyroidism can lead to a type of tumor that looks very similar. It is also important to get a family history to check for a disease called cherubism that causes similar symptoms in children.

Imaging plays a big part in the diagnosis. The X-ray or CT scan may show a less dense area, which can be small near a tooth or larger and involve a good portion of the jaw bone. For smaller areas, simple X-rays may be enough, but for larger areas, a 3D CT scan provides a better understanding of bone damage.

Osteoma often shows up by chance while having imaging done for another reason. With X-rays, a clear, dense lesion can be seen. CT scans help show the size and location of the lesion, which is crucial when planning surgery.

In Osteochondroma, X-rays show a continuity of the marrow space with the underlying normal bone, which hints that the lesion is an osteochondroma. CT imaging gives a more realistic picture of the lesion’s location and shape while planning for surgery. A type of MRI is recommended before surgery to assess the joint areas.

For Osteoblastoma, the X-ray findings may differ. Depending on the degree of calcification, spots of less dense and dense areas can be observed. Larger lesions might not have a clear border distinguishing them from the surrounding bone.

Treatment Options for Non-Odontogenic Tumors of the Jaws

Osteosarcoma, which is a kind of bone cancer, is primarily dealt with through surgery. During the surgery, the surgeon removes the tumor and some of the surrounding healthy tissue. Sometimes after the tumor is removed, some reconstruction may be needed. The success of this type of surgery depends mostly on if the surgeon was able to completely remove the cancer. If the tumor is in an area where it’s hard to remove, or if it’s especially fast-growing, doctors might also consider using chemotherapy before or after surgery.

Fibrous Dysplasia is a bone disorder where some bone is replaced by fibrous tissue, which can cause the bones to expand. The symptoms can stabilize as a person matures, so doctors have to consider carefully when would be the best time to intervene. In mild cases where the facial expansion has adapted well with the patient, no surgery may be necessary. When surgery is required, it often involves reducing and reshaping the affected bone. Since recurrence is more likely to happen while the bone is still growing, doctors often prefer to delay surgery until the patient is an adult.

Central Giant Cell Granuloma involves lesions which can be managed through either surgery or non-surgery methods. The type of surgery depends on factors like the location, size, and how aggressive the lesion is. In non-surgical treatment, doctors often consider it for smaller, less aggressive lesions. Sometimes, for larger lesions, non-surgical treatment can be used simultaneously with surgery for better results.

Osteoma is a benign, slow-growing bone tumor. The management of osteoma depends on the symptoms that it causes. When it’s small and isn’t causing any other issues, it can just be closely watched. If it’s causing symptoms though, surgeons often go ahead and remove it entirely.

Osteochondroma, a benign bone tumor that usually forms near a joint, is generally treated with surgical removal. If it’s in the joint and affecting its function, the surgery may involve removing the entire joint, followed by joint replacement surgery. If the tumor is small and affects less than half of the joint, it can generally be removed directly.

Osteoblastoma is a bone tumor that can be difficult to diagnose accurately. Treatment for osteoblastoma varies depending on how aggressive the tumor is. Some are well managed with just close supervision or with surgical removal of the tumor and some surrounding healthy tissue. If the tumor is aggressive and found in a young person, chemotherapy may also be an option. In cases where the osteoblastoma returns, it’s important to determine if it’s the same tumor recurring or if it’s a new case of osteosarcoma, a more serious type of bone cancer.

What else can Non-Odontogenic Tumors of the Jaws be?

Osteosarcoma, fibrous dysplasia, central giant cell granuloma, osteoma, osteochondroma, and osteoblastoma are all medical conditions that need to be differentiated from other similar conditions. This can sometimes be challenging, but certain clinical traits or behaviors can help in their identification. Here’s a simplified comparison with other conditions:

Osteosarcoma could be confused with:

• Osteoblastoma: However, osteoblastomas are typically harmless and don’t spread to other parts of the body.
• Ossifying fibroma: But this can be identified by its lack of loss of the layer just beneath the bone surface.
• Osteomyelitis: This might look similar on x-rays but the course of the disease differs and it’s unlikely to cause tingling or numbness, which is a symptom of nerve invasion.

Fibrous dysplasia could be mistaken for:

• Ossifying fibroma: It’s not easily distinguished but is typically found in areas where teeth reside and has well-defined lines of radiolucency.
• Segmental odontomaxillary dysplasia: It results in the failure of certain teeth to emerge and causes gum overgrowth.
• Paget’s disease: Typically seen in older people, it’s more likely to be associated with pain and changes in the shape or appearance of bones.

Central giant cell granuloma might resemble:

• Brown’s tumor of hyperparathyroidism: But this condition is usually present in multiple and with altered bone effects.
• Cherubism: A genetic disorder that causes many bone-destroying lesions, typically in the lower jaw.
• Conditions like Noonan syndrome, neurofibromatosis type 1, and aneurysmal bone cysts.

Osteoma could be compared with:

• Bony exostoses: Can be differentiated by no more growth after puberty and are usually multifocal.
• Osteoid osteoma: Pain is more dominant and there is a rapid expansion.
• Complex odontoma: It shows greater density in radiographic assessment.

Osteochondroma is often confused with:

• Malignant lesions: But these will cause damage to surrounding tissues and symptoms like numbness.
• Conditions such as condylar hyperplasia and hemimandibular hyperplasia.

Osteoblastoma may be considered instead of:

• Osteoid osteoma: It’s often smaller and responds well to certain medications.
• Low-grade osteosarcoma: This also has similar characteristics but could spread to the lungs and cause problems with surrounding nerves.

What to expect with Non-Odontogenic Tumors of the Jaws

Osteosarcoma

Osteosarcoma is a severe malignancy that spreads aggressively to other parts of the body. However, Osteosarcomas found in the jaws are less severe and have a better chance of recovery compared to those found in the central part of the skeleton. There’s a 20 to 25% chance of this cancer spreading to the lungs. Within five years, about 77% of patients diagnosed with non-spread osteosarcoma, which has been completely removed, survive. Obtaining a clean removal of the cancer is the most significant factor in determining survival rates. Other factors that influence the prognosis include age over 60, the severity of the tumor, the location of the tumor, and in some cases, the use of additional chemotherapy. Local return of the disease is more common than it spreading to other areas.

Fibrous Dysplasia

There’s a small chance (1%) for Fibrous Dysplasia to transform into a more serious condition like osteosarcoma, although this is very rare. This malignant transformation is more commonly seen in those who have undergone radiation therapy. However, going from Fibrous Dysplasia to forms like fibrosarcoma and chondrosarcoma have also been reported.

Central Giant Cell Granuloma

Central giant cell granuloma can behave aggressively, causing local destruction or it may be mild and respond well to non-surgical treatments. The chance of the disease returning is higher in these aggressive forms, especially if not completely removed. It usually reoccurs within the first 12 to 18 months. In more severe cases, there’s a high rate of recurrence reported between 40 to 70%.

Osteoma

Osteomas have a good overall prognosis, and it’s extremely rare for it to return after surgical removal. No cases of it evolving into a more severe form have been reported.

Osteochondroma

Removing an Osteochondroma is usually therapeutic and the rate of recurrence is low. Malignant transformation of craniofacial osteochondromas is also rare with only two reports within the literature.

Osteoblastoma

Osteoblastoma has a high recurrence rate, at up to 20%. This type of tumor can spontaneously evolve into a more serious form or could represent a low-grade osteosarcoma. That’s why it’s important to routinely check up on these patients with clinical and radiographic examinations.

Possible Complications When Diagnosed with Non-Odontogenic Tumors of the Jaws

Osteosarcoma, a type of cancer, can cause complications due to its destructive nature. It often requires extensive surgeries, like wide resection of the jaws, and further reconstruction.

Fibrous dysplasia refers to a condition that can cause noticeable facial asymmetry in children and teenagers. This can be distressing for patients and their families. Complications due to fibrous dysplasia are usually a result of surgery, and the issue can reoccur if the patient is still in the active phase.

Central giant cell granuloma is a condition that can result in complications due to the destructive nature of the lesions. This includes the loss of teeth or tooth buds. If the lesions cause erosion of the cortical bone surrounding nerves, particularly the inferior alveolar nerve, impingement or pressure on the nerve can occur. This is generally resolved once the nerve is repositioned.

Complications from osteomas, bone tumors, depend on their location and the surgical procedures undertaken for their removal. These complications are tied to the tumors’ functional impact and the surrounding anatomical structures.

Osteochondromas are bone protuberances that can cause complications if they press against the temporomandibular joint. These complications are usually not specific to osteochondromas and can happen with any surgical intervention on the temporomandibular joint.

Osteoblastomas are another type of bone tumor. If they’re small, the complications after local curettage, a surgical procedure to remove tissue, can be minimal. However, if osteoblastoma is of an aggressive type, there can be substantial health complications and in rare cases, even death.

Possible Complications:

• Extensive surgeries (osteosarcoma)
• Facial asymmetry (fibrous dysplasia)
• Surgery-related complications (fibrous dysplasia and osteochondroma)
• Loss of teeth or tooth buds (central giant cell granuloma)
• NERVE impingement (central giant cell granuloma and osteochondroma)
• Function and location-related complications (osteoma)
• Health complications and potential death (aggressive osteoblastoma)

Preventing Non-Odontogenic Tumors of the Jaws

The causes of non-tooth related tumors in the jaw are not fully known, mainly because these conditions are quite rare. As a result, it’s hard to say how to prevent them, as there’s very little understanding of how they develop. Once a doctor has diagnosed this condition, it’s extremely important for patients to understand their situation. This means knowing what the diagnosis means, what to expect, and the different ways to treat it. Having this knowledge will enable patients to participate in making decisions about their treatment, and enable them to follow the treatment plan more closely.