Malathi, E. Rajesh, U. Tamilarasi and K. M. K. Masthan

Department of Oral Pathology, Sree Balaji Dental College and Hospital, Bharath University, Pallikaranai, Chennai – 600100.  

DOI : https://dx.doi.org/10.13005/bpj/1021

Abstract

Oral malignant melanoma is a rare neoplasm of melanocytes  commonly affecting the middle age group and it is more common skin rather than oral cavity . Oral malignant melanoma is a rare aggressive neoplasm of the middle age. This malignancy commonly affects males and  it is more frequently seen on the hard palate and gingiva

Keywords

melanocytes; proliferations; Histopathological

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Copy the following to cite this article: Malathi M, Rajesh E, Tamilarasi U, Masthan K. M. K. Malignant Melanoma of Oral Cavity. Biomed Pharmacol J 2016;9(2).

Copy the following to cite this URL: Malathi M, Rajesh E, Tamilarasi U, Masthan K. M. K. Malignant Melanoma of Oral Cavity. Biomed Pharmacol J 2016;9(2). Available from: http://biomedpharmajournal.org/?p=8147

Introduction 

Malignant melanoma (MM) is a neoplasm  of epidermal melanocytes, which are located primarily in the skin and mucosa .cutaneous melanomas are more common rather than the oral melanomas ^2,3

It is more common on white skinned individuals than  the dark skinned ones  and the lesion accounts for 0.2 % of all melanomas  but it is extremely rare in united states .

In oral cavity it represent less than 2% of all melanomas

The  Japanese, Black Africans, Native Americans, and Hispanics are most commonly affected by oral melanomas ¹³

Etiology

The factors affecting the cutaneous melanoma are environmental and genetic factors which may have a positive  familial history ^1,12. Etiology for oral mucosal melanomas was unknown  and there was no relationship between any physical or chemical events ⁷ . But sometimes intraoral melanocytic proliferations (nevi) may be the source for oral malignant melanomas. In 1975 clark postulated the  2 growth pattern for melanoma .

Radial growth phase 

In this phase  the neoplastic cells are limited only  to the epidermis and some may enter into the basement membrane destroying host cell immunologic response

Vertical growth phase 

In this where neoplastic cells populate the underlying dermis metastasis is possible in this phase

Types of melanomas

Cutaneous melanomas

superficial spreading melanoma , nodular melanoma , lentigo maligna melanoma and acral lentiginous melanoma

ABCDE rule of melanoma 

asymmetry , border , color , diameter and elevation

Clinical features

There are 5 clinical types –  pigmented nodular , pigmented macular , pigmented mixed , nonpigmented nodular and nonpigmented mixed type^.[14].Malignant melanoma may occur with or without radial growth phase^[2] The color may be uniform and some lesions  appears as   black, grey, purple, or even reddish. The lesions are asymmetric, irregular in outline, and occasionally multiple. The surface architecture varies for oral melanomas ranging  from  nodular and macular to ulcerated^.[4,5,7] Amelanotic oral malignant melanoma (AOMM) :  some tumors are amelanotic which is of rare type . lesion is erythematous or pink ,sometimes it may be eroded or nodule . but the diagnosis of the lesion may be confused with other tumors , only by the histopathological examination the final diagnosis of the lesion can be made  ^.[15] Pain is an uncommon symptom of malignant melanoma, generally found in the advanced stages^.[3,5,8] The tumor causes extensive destruction of the underlying bone in 78% of cases^.[5]

Histopathological features 

Abnormal melanocytes are seen in the epithelial and connective tissue junction and there is a  high density of melanocytes, atypical cells present in the  oral melanotic lesion  which is diagnosed as oral malignant melanoma.⁶

In amelanotic melanoma , the melanoma cells have melanin granules but there is no production of melanin is seen . this less production causes difficulty in diagnosing as it may represent some other tumors

Immunohistochemical studies shows  S-100 protein, MART-1, and HMB-45 reactivity of the lesional cells in  melanomas from other malignancies^.[6]

Diagnosis

Diagnosis of melanoma may be difficult because of its small biopsy size , lack of clinical or may be due to variety of reasons⁷. CT and MRI studies were  done to know the metastases occurring in  the cervical and submandibular  lymph nodes. Incisional biopsy is most common choice for diagnosis^.[4]

Differential diagnosis

Differential diagnosis of oral melanomas are  oral melanotic macule, smoking-associated melanosis, medication-induced melanosis  melanocytic nevi of the oral mucosa, blue nevi, nevi of Spitz, Addisons disease, Peutz-Jeghers syndrome, amalgam tattoo and many other conditions .

Management

Surgery excision is first line of  treatment, but it is  difficult due to  anatomic restraints. Jaw resection and lymph node dissection is done when the bone or lymph nodes are involved .chemotherapy  and radio therapy were the other forms of treatment  ^4-6

Prognosis and survival

Oral melanomas have poor prognosis than cutaneous melanomas. Cutaneous melanomas can be graded by Clark levels or the Breslow tumor thickness grading system. The clark classification assesss  the depth of invasion, whereas Breslow

system measures the thickness of the tumor and depth of the tumor from the surface epidermis .  When the tumor thickness is increased there is a high risk for developing metastatic lesions.

Both these system shows the 5 year survival rate . Factors that are significant in disease  survival include high clinical stage at presentation, tumor thickness greater than 5 mm, , absence of melanosis, presence of vascular invasion,development of nodal and distant metastases.^5,6,8

References

1. Hicks MJ, Flaitz CM. Oral mucosal melanoma: Epidemiology and pathobiology. Oral Oncol 2000;36:152-69.
2. Freedberg IM, Wolff K, Austen KF, et al. Dermatology in general medicine. 5th ed. Mc Graw-Hill: United States; 1999. p. 981,1097.
3. Steidler NE, Reade PC, Radden BG. Malignant melanoma of the oral mucosa. J Oral Maxillofac Surg 1984;42:333-6.
4. Greenberg MS, Glic KM. Burket’s oral medicine. 9th ed. BC Decker:Hamilton; 2003. p. 131-2,214-5.
5. Prabhu SR, Wilson DF, Daftary DK. Oral diseases in the tropics. Oxford University Press: New York; 1992. p. 460-1.
6. Neville BW, Damm D, Allenc R, Bouquot JE. Oral and maxillofacial pathology. 2nd ed. W.B Saunders: Philadelphia; 2002. p. 334,376-80.
7. Silverman S. Oral cancer. 5th ed. BC Decker Inc: Hamilton, London; p. 155-7.
8. van der Waal RI, Snow GB, Karim AB, Van der Waal I. Primary malignant melanoma of the oral cavity: A review of eight cases. Br Dent J 1994;176:185-8. 9.
9. Robertson GR, Defiebre BK, Firtell DN. Primary malignant melanoma of the mouth. J Oral Surg 1979;37:349-52.
10. Reddy CR, Ramachandra T, Ramulu C. Primary malignant melanoma of the hard palate. J Oral Surg 1976;34:937-9.2003;96:404-13.
11. Bina SH. Primary malignant melanoma of the oral cavity in Iranians (review of 18 cases). J Oral Med 1979;34:51-2.
12. Tremblay JF, O’Brien EA, Chauvin PJ. Melanoma in situ of the oral mucosa in an adolescent with dysplastic nevus syndrome. J Am Acad Dermatol Tanaka N, Amagasa T, Iwaki H, Shioda S, Takeda M, Ohashi K, et al.Oral malignant melanoma in Japan. Oral Surg Oral Med Oral Pathol 1994;78:81-90.
13. Tanaka N, Mimura M, Kimijima Y, Amagasa T. Clinical investigation of amelanotic malignant melanoma in the oral region. J Oral Maxillofac Surg 2004;62:933-7.
14. Rajendran R, Sivapada Sundaram B. Benign and malignant tumors of the oral cavity. Shafer, Hine, Lavy, editors Shafer’s Text book of Oral Pathology India: Elsevier2009:120-7.

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