Introduction
Oral mucosal melanomas are a rare and aggressive type of cancer that develops in the tissues lining the mouth. These melanomas arise from melanocytes, the cells responsible for producing pigment, and can occur on the lips, gums, cheeks, tongue, and other oral structures. Due to their aggressive nature and potential for delayed diagnosis, oral mucosal melanomas present significant challenges in terms of treatment and management.
What Are Oral Mucosal Melanomas?
Oral mucosal melanomas (OMMs) are relatively rare oral cancers that occur in the oral mucosa or soft tissue. These have very aggressive clinical and pathological features. Medical and dental research indicates that the mean five year survival rate is only 15 percent for all oral mucosal melanomas. Besides, OMMs account for up to 25 percent of all head and neck mucosal melanomas. These exhibit a multitude of genetic alterations. Hence, each of them exhibit a unique pathobiological behavior.
What Are the Symptoms of Oral Mucosal Melanomas?
OMMs are different from cutaneous (skin) melanomas in several aspects. It is because the clinical course of these lesions is radically different from cutaneous melanomas. Various clinical aspects for consideration are:
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Growth: OMM lesions are usually painless and fast growing in nature. The lesions become large and have the potential for regional metastasis.
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Site: They are different from cutaneous melanoma lesions regarding the location. It is because these occur at sites which are not exposed to solar radiation. The palate of the upper jaw and the gums (upper arch) are the most commonly affected segments of the oral cavity.
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Age: Men above 60 to 70 years are most frequently affected.
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Shape: These lesions are very irregularly shaped in the oral cavity. There is a visible change of color in the oral mucosa in that region. For example, there can be a color change in normal pigmented lesions, such as brown, blue, gray, or black. The initial lesions are nodular, macular, or plaque like. Nodular melanoma resembles a growth or lump, whereas macular melanoma is a flat and discolored area in the mouth. However, the advanced lesions tend to get ulcerated and bleed. The most common reason for the initial lesions to progress to an advanced stage is the painless nature of these lesions.
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Other Symptoms: As time progresses, the patient can also notice additional symptoms like drooling of saliva and voice alteration.
What Is the Prevalence Rate of Oral Mucosal Melanoma?
OMMs account for about 1.3 percent of all melanoma lesions in the body. The prevalence of OMM lesions is approximately 55 percent of all the head and neck mucosal melanomas. Out of those, about 70 percent affect the nasal cavity or the paranasal sinuses. On the contrary, about 25 percent of lesions affect the oral mucosa. Oral mucosal melanomas are listed in 0.26 to 0.5 percent of all known oral malignancies or cancers. For many elusive reasons, the prevalence rate of these cancers is higher in Asia than in North America, or Europe. However, their incidence (new cases) and prevalence in the African continent remain unknown.
What Is the Metastatic Potential of Oral Malignant Melanoma?
OMMs are unique in their cause because they are not associated with any carcinogenic agents. The prognosis for such aggressive tumors is poor because they are diagnosed late in the disease course. The term metastasis refers to the occurrence of another tumor at a different site than the primary tumor. The high regional metastasis potential of OMM can hamper the prognosis rates. Various case reports suggest that in nearly 85 percent of affected individuals, OMMs can metastasize to liver, lungs, bone, or brain by blood dissemination.
What Is the Microscopic Picture of Oral Mucosal Melanoma?
Under the microscope, the lesions of oral mucosal melanoma can be differentiated because of the distinctive patterns of the tumor cells. Three different patterns of melanocytes can be recognized in these tumors: radial pattern, deep invasive pattern, and nodular pattern.
What Is the Differential Diagnosis of Oral Mucosal Melanoma?
The differential diagnosis for oral mucosal melanomas is:
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Melanotic macules.
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Smoking-associated melanosis.
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Inflammatory oral pigmentation.
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Systemic medication induced melanosis.
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Melanoplakia.
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Melanoacanthoma.
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Oral manifestation of Addison’s disease.
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Oral pigmentation in Peutz-jeghers syndrome.
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Oral nevi.
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Amalgam tattoo.
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Kaposi’s sarcoma.
What Is the Diagnosis & Management of Oral Mucosal Melanoma?
A thorough medical and dental history is foremost in the correct diagnosis of OMM. An in depth examination of the oral cavity and neck is performed by the dentist or an oral surgeon. It also requires multidisciplinary team intervention. The team should comprise inputs from health providers like otorhinolaryngologists (ear, nose, and throat specialists) and general practitioners. Atypical signs of lesions, the clinical nature, and the patient symptoms must be contemplated for the correct surgical strategy, as it may improve the prognosis. Various management options depend on the staging of the tumor.
1. The recommended treatment is excision and ablative surgery along with excision of tumor-free margins. The surgery can be done in combination with chemotherapy (use of anti-cancer medicine).
2. Some oral surgeons recommend radiotherapy or immunotherapy. Immunotherapy uses an individual’s own immunity to fight tumor cells. On the other hand, radiotherapy employs radiation to target and eliminate tumor cells. These modalities are effective in complete elimination of the cancer cells.
Conclusion
To conclude, oral mucosal melanomas are aggressive tumors. They should be diagnosed at an early stage to save the patient from the high risk of death and for improving long-term prognosis. They are unique in their tendency to be painless. Further, they can proliferate with a regional spread and carry a high metastatic potential. Hence, surgical intervention along with chemotherapy, radiation, or immunotherapy can be useful in tumor eradication.
