Tumours in the area of th head, neck and mouth

Ignorance creates fear, and this text should alleviate the fears of its viewers to some extent. How does a tumor develop and what exactly is a tumor; this will be explained in the following text. Both animals and human beings are composed of many different cells that form groups; different groups of cells form organs with specific functions. Every cell contains genetic information in its nucleus, which assigns a particular task to the cell. This genetic information is contained in several long strands that consist of sugar, phosphate, and four different bases (adenine, thymine, guanine, cytosine). These bases are lined up in a row to form the so-called DNA strand. Pairs of these strands combine to form chromosomes. Everyone must be familiar with the fact that the microprocessor of a computer only knows “power off" and “power on;” i.e., 1 and 0. The binary coding of this impulse can represent numbers, letters, and many other symbols; e.g., the binary code 01000010 stands for the letter “B.” DNA strands in a cell work in a similar fashion; it is always 3 base pairs that code for one amino acid, which is a building block from which the cell produces proteins. Proteins form the basic framework for all kinds of cell organs or organelles.

The interior of a cell is somewhat more complex than that of a computer; the coding does not just depend on the arrangement of base pairs but also on the manner in which the DNA strand is organized, i.e. how it is folded. Therefore, this DNA strand determines the type of cell it is going to become, what tasks it will have to perform, and when it is supposed to die. Besides the nucleus, a cell comprises various cell compartments; e.g., there is a “stomach” as well as “factories,” in which new proteins are produced from amino acids. Other factories use sugar molecules to produce carbohydrates, while others use fatty acids to produce fats. Also, every cell has a so-called cytoskeleton. Not only does this cytoskeleton provide the cell with its shape, but it also transports substances within the cell; like a series of huge conveyor belts, it transports substances within the cell from one place to another. So basically, a cell is put together in the same way an entire organism is put together, but on a much smaller scale. The DNA is like a recipe book in which all instructions are written down with great precision. These processes must be executed in an organized manner; otherwise, the result is chaos.

Imagine a young heart cell that developed from blood precursor cells. It grows and settles down at the location of the future heart. There, it finds its peers, and they all multiply and join to form a primitive precursor organ. The information required by the cells for finding their proper location is coded in the nucleus as well. Other cells, the so-called guiding cells, also help the heart cell to find its right location. Many of these guiding cells atrophy after embryonic development; sometimes, cysts may form out of such cells. Our heart cell has now reached its destination, where it multiplies and links up with its peers. Cell–cell contacts form; this is noticed by the cell nucleus, which immediately releases information about the tasks that need to be done; e.g., it may dictate the cell to produce more of the protein myosin and integrate it into the cytoskeleton. The corresponding proteins are immediately produced in the cell factories and built into the cell skeleton. At some point, the primitive heart cell begins to concentrate because of the new proteins, and the cell network results in a heartbeat. Just as human beings have a certain lifespan, the heart cell also has one, after which it must make room for new cells. Because work leads to wear, the cytoskeleton ages. A biologist terms this programmed cell death as apoptosis. When the time arrives, the nucleus notifies the cell to destroy itself; i.e., to initiate apoptosis. At that point, we arrive at our topic of cancer. If apoptosis is not executed properly, this cell, which “does not want to die,” could turn into a cancer cell. However, although our heart cell “does not want to die,” it does not want to multiply either. Nevertheless, its defective function is immediately detected by special guard cells (the immune system), who simply eliminate or destroy it.

Imagine another heart cell. As soon as the cells reach their destination, they normally begin to divide, and they continue to do so until they run out of space. Special receptors on the cell surface signal that the cell is surrounded by its peers and does not need to continue dividing; it has to assume its originally assigned function instead, which in this case is the production of myosin. Sometimes, both apoptosis and the cell division mechanism do not work. As a result, this other cell keeps multiplying, even though there is no more space available. It “does not want to die” either, because the apoptosis mechanism does not work anymore. Therefore, a lot has gone haywire in the cell, or more precisely, in the DNA strand, where signaling pathways do not work anymore, the wrong proteins are being produced, etc. Every new descendent cell has the same defect, and these descendent cells also divide unlimitedly. Moreover, since the entire cell metabolism has gone haywire, more and more defects accumulate in these descendent cells. They are so severe that the cell either dies immediately or a true tumor cell develops. Because a malignant tumor has not formed at this stage, the guard cells (our immune system) notice the rapidly dividing defective cells immediately and destroy them. Unfortunately, not all can be destroyed because some cells survive the attack of the immune system, and through newly accumulated defects in the genetic information, these cells succeed in fleeing the immune system. Through spontaneous mutations, some of the descendent cells acquire the capability to detach from the cell network. They produce an enzyme that allows the cell to eat through vascular walls. Therefore, the now malignant cell reaches a foreign location, leading to metastasis.

In this case, the primum; i.e., the cell of origin, was a heart cell. It is not always possible to trace the origin of these tumor cells because the accumulated defects cause the cells to lose more and more of their original form/function. Such tumors are called malignant tumors with an unknown primum. Obviously, all this work (cell division, migration) consumes a lot of energy. This is also the reason why human beings die; either the cell settles in at a very unfavorable location from where it cannot be removed, or the body loses so much energy that it dies from energy depletion. In most cases, it is a mixture of both. Luckily, fewer and fewer patients are dying from a malignant tumor, although the frequency of tumors is increasing. The reason for reduced deaths lies in perpetually improved therapeutic possibilities; however, an early recognition is equally important.

How do these defects occur? If we look at our heart cell, we can see that radioactive irradiation may damage the DNA, but certain chemicals may also harm them. Depending on the tissue, there are different ways in which it can be damaged. Lung cells do not tolerate cigarette smoke, liver cells do not tolerate alcohol, and kidney cells do not tolerate heavy metals. The entire issue is further complicated by the immune system, which—as we have learned—can recognize and also eliminate tumor cells. However, it can also trigger tumor formation through various factors; e.g., chronic inflammatory stimuli. Therefore, the development of a malignant tumor is an evolutionary process that occurs in one’s own body, and it is caused by a deregulated cell. Now it becomes clear as to why substances capable of damaging genetic information can trigger tumor formation. In short, anything that can disorganize the recipe book of a cell can cause tumor formation. Some individuals inherently have “better order” in their cell library, whereas others have less of it. This is why there are families with a predisposition for certain tumors. Many factors contribute to the affinity for tumor development, including ones own genetic information, the amount and frequency of exposure to harmful substances, etc. Another factor is the immune system, which is in turn modulated by our psyche. All these aspects are closely interrelated in a very complex manner; the more people understand these issues, the better they can arrange their lives for a balanced lifestyle, through which they can counteract the degeneration and abnormal multiplication of cells.

When a doctor speaks about a tumor in the Latin sense, the term is not the same as layman’s understanding of the word. Patients always take the term “tumor” to mean a malignant mass, while a doctor would speak of a malignant mass as a carcinoma and not a tumor. Every mass should be investigated to clarify whether it is malignant or benign. If a definite diagnosis cannot be achieved by clinical examination and/or imaging (e.g. computed tomography), a tissue sample (biopsy) is obtained from the mass. A pathologist examines the specimen under the microscope and establishes its origin, that is to say, the type of cell that is responsible for the increased growth.
Depending on the origin and the main changes in the tissue, the pathologist can establish the aggressiveness of the mass. It is only after pathological examination that we can ascertain the type of mass we are dealing with; nonetheless, a rough estimation can be made by evaluating the clinical features of the mass. The following factors generally indicate a benign mass:

  • structures surrounding the mass are not destroyed but only displaced
  • the mass has regular edges
  • slow growth
  • no other clinical features such as night sweats or weight loss

It is important that any changes are investigated promptly because it is often possible to determine if surgery is required at a very early stage. The earlier a malignant mass is removed, the better the prognosis.

There are a multitude of different, benign and malignant tumors - so called oral cancer - in the area of the mouth, neck and head.  Let’s look at some of them together.

Tongue Carcinoma

Tongue carcinoma is malignancy of the tongue cells, which are also known as plate epithelial cells. Cigarette smoking, alcohol consumption, and chronic wounds or irritation to the mucosa can all contribute to the development of tongue carcinoma. In the initial stages of the disease, the patient may notice a small, hard lump on the tongue, as demonstrated in this photo. Some patients may also notice a cauliflower-like eruption on the tongue that refuses to heal, as one can see here. Here are a few images of tongue carcinomas. However, there are many different forms of tongue carcinoma, which is why an individual should visit his/her doctor if he/she has a wound that refuses to heal.

As a general rule, all wounds in the oral cavity that do not heal after one week should be evaluated by a doctor. If there is no plausible explanation for the wound not healing and/or treatment is unsuccessful, a biopsy (tissue sample) should be taken and sent for histological evaluation in order to definitively rule out or confirm tongue carcinoma. It is important that the biopsy is performed by an experienced physician because the sample can get damaged during biopsy, rendering it useless for pathological evaluation. The biopsy should be performed in a specialist clinic that can, in the event of a tongue carcinoma being diagnosed, also carry out the necessary treatment.

When diagnosed in the early stages, the prognosis of tongue carcinoma is good and full recovery is possible. Treatment includes surgical resection and elimination of any chronic wounds or irritants that may have caused the tumor. Lifestyle modifications, i.e., discontinuation of cigarette smoking and/or alcohol consumption, also form a part of treatment.

Tooth Cancer (Odontogenic Tumors)

Tooth cancer is a colloquial term for odontogenic tumors, which arise from cells involved in tooth development. The cells that make up our teeth can also cause tumors; fortunately, these tumors are usually benign (malignant tumors are rare).  Benign tumors of the oral cavity include the following:

  • Odontoma
  • Cementoblastoma
  • Ameloblastic fibroma

Odontomas usually grow during tooth development and may comprise enamel, dentine, and cementum, similar to a real tooth. A compound odontoma has the three separate dental tissues (enamel, dentin, and cementum), but it may present a lobulated appearance where there is no definitive demarcation of separate tissues. A complex odontoma is unrecognizable as dental tissues, usually presenting as a radioopaque area with varying densities.
An ameloblatic odontoma, on the other hand, is a benign odontogenic tumor having histological characteristics of both an odontoma and an ameloblastoma. It differs from the classic odontoma in that it tends to recur.

A cementoblastoma comprises a build-up of cementum in layers; often the tooth root is resorbed and the periodontal space degenerates because of pressure applied by the growng tumor.

Ameloblastic fibromas are composed mainly of fibrous or fully developed connective tissue, and they usually affect patients between the age of 10 and 20 years. They generally develop in the posterior teeth of the lower (mandibular) jaw. In 50% cases, an unerupted tooth is involved.

In addition to benign tumors, semi-malignant tumors may also involve the oral cavity. While its true that ameloblastomas do not tend to metastasize (spread of secondary tumor tissue), they often lead to local recurrences. Ameloblastomas occur most often in individuals aged between 30 and 50 years, and they usually involve the lower posterior teeth. An ameloblastoma is a semi-malignant (partly malignant ) tumor that stems from the primitive cells of the tooth bud. Our teeth, which are formed during embryonic development, comprise different types of cells. Together, these are known as the tooth bud or the tooth germ. Tooth enamel, for example, is made up of cells called ameloblasts. These cells degrade after tooth development is complete. However, residual cells often remain in the jawbone after tooth development is complete.

Uncontrollable division of these residual ameloblasts at any point in life leads to the formation of an ameloblastoma. Ameloblastomas do not metastasize; however, they often recur after primary tumor resection. Therefore, they are referred to as semi-malignant tumors. Achieving wide surgical margins during resection is essential to prevent recurrence from residual cells or tumor material.

Another semi-malignant tumor occasionally found in the jaws is the myxoma, which is a fast-growing bone tumor that tends to occur only in the jaw bone. These tumors often tend to recur after apparently successful therapy. Because they can also transform into myxosarcomas, which are malignant, these tumors are considered partly malignant.

Malignant tumors of the oral cavity are called odontogenic carcinomas and are rare in occurrence. The most common carcinoma in the area of the jaws is the squamous cell carcinoma. These develop from cells in the oral mucosa (lining), called epithelial cells.

Irrespective of being benign or malignant, all tumors are removed surgically and analyzed histologically (microscopically). An adequate surgical margin is required. Sometimes, it is necessary for the jaw to be stabilized with metal plates after removal of the tumor (osteosynthesis).

Alternatives to Surgery

As is the case with almost all malignant and semi-malignant tumors, surgical removal is the treatment of choice when possible. If the size of the tumor impedes surgical removal, radio- or chemotherapy are possible options. Surgery-related risks are specific to each tumor. Therefore, it is necessary that the level of risk related to surgery is discussed with the attending physician prior to surgery.

Early diagnosis and treatment are very important. An early symptom of an odontogenic tumor, regardless of whether it is benign or malignant, is tooth migration. If one gets the feeling that his/her teeth no longer fit together as they used to, and if this feeling does not disappear after a couple of days, a visit to the dentist becomes essential. A panoramic X-ray can provide important information.

Changes in the mucosa are to be followed up in the same way. Every abnormality in the mucosa that does not cure itself within a week should be examined by a dentist. Individuals who wear a prosthesis must remove it from the mouth; the wound disappears if it is the result of a pressure point. If not, then the wound should be examined by a medical practitioner. Do not feel embarrassed about wanting to consult several doctors, as not every doctor will be familiar with odontogenic tumors, sometimes leading to misdiagnosis. Odontogenic tumors rarely metastasize and most are benign; nevertheless, they must be removed as they cause local problems through their expansive growth.

Salivary gland tumors

Salivary gland tumors are benign in 75% cases and malignant (cancerous) in the remainder. By far the most frequent benign salivary gland tumor is pleiomorphic adenoma in the parotid gland, which grows slowly but has the ability to bury itself deep in the tissue. In the case of malignant tumors there are a large number of sub-types which are differentiated by their fine tissue characteristics, the most frequent being mucoepidermoid, adenocystic, acinus cell, and squamous cell carcinomas, and adenocarcinoma.

Parotid gland tumors

Parotid gland tumors are benign in 80% cases and malignant in the remaining 20%. Regardless of the tumor being benign or malignant, early removal of all parotid tumors is recommended as a protocol because surgical risks increase with growth of the tumor. In addition, a benign tumor can turn malignant in the course of time. Good follow-up care with regular medical check-ups is very important to facilitate early detection of recurrence, which is a possibility.

The procedure for surgical removal is defined by the size of the tumor and its proximity to the facial nerve, which enters the parotid gland, divides into five branches, and eventaully exits with its final branches that supply the individual mimetic facial muscles. Clinically speaking, the fan-shaped division of the facial nerve divides the gland into an outer and inner lobe. Most tumors occur within the outer lobe.

For an outer lobe tumor, the nervebranches are very carefully charted under a surgical microscope before attempting removal of the outer lobe (lateral parotidectomy). Should the tumor lie below the nerve branches, i.e., in the inner lobe, a lateral parotidectomy is performed in addition to removal of the part of the gland below the nerve branches (subtotal parotidectomy). This surgery is complicated as removal of the inner lobe involves careful separation of the nerve branches from the gland without injuring any of them.

In case of malignant tumors, the entire parotid gland, including all lymph nodes in the area, is removed (total parotidectomy). This is very important because the parotid gland contains 20–30 lymph nodes, and early secondary growths (metastases) of the tumor can be found in these lymph nodes. If the tumor infiltrates the facial nerve, then parts of the facial nerve must also be removed (radical parotidectomy). If possible, a reconstruction of the facial nerve is subsequently performed.

The most significant surgical risks are permanent paralysis of the facial nerve, salivary fistula formation, and sweating while chewing (hyperhidrosis parotidea masticatoria). Permanent paralysis of the facial nerve may occur when the facial nerve is injured during excision of the parotid gland and left untreated. A salivary fistula is formed when parotid gland tissue is present within the wound, allowing saliva to emerge through the wound. These fistulae usually heal unaided; a second surgery is rarely necessary.

Through sectioning of the skin and removal of parts of the parotid gland, small nerve branches, some of which control sweat glands in the skin and others that control the salivary gland itself (to stimulate saliva production), are inevitably damaged. After surgery, these damaged nerves may regenerate and make false connections with the sweat glands in the surgical area. This process can take 3–12 months and may result in the patient sweating over the surgical site while eating (chewing sweats). These chewing sweats can be treated effectively and simply by applying aluminium chloride-based pastes on the skin. Nowadays, botulin toxin A injections, which have a long-lasting effect, are also commnoly used for treating this condition.

This is not a complete list of the tumors in the jaw area. Every surgery must be discussed and planned individually as each tumor is different in nature. What is important is to look for a clinic where tumor resections are regularly performed and where adequate care will be provided by a multidisciplinary team.

This post is also available in: German

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