Introduction:
Malignant melanoma is a neoplasm of melanocytes or of the cells that develop from melanocytes [1]. Once considered an uncommon disease, the annual incidence of melanoma has increased dramatically over the last few decades [2]. Malignant melanomas comprise approximately 1.5% of malignancies and 20% of these involve the head and neck region [3]. The first reported case of tonsillar metastasis from cutaneous malignant melanoma was in 1912 by Schmidt [4]. Since then 24 cases of tonsil metastasis from a cutaneous malignant melanoma have been reported. The other reported sites include the nasopharynx, larynx, lip, pharyngeal wall, gingiva, nasal cavity, pyriform sinus, palate and maxillary sinus. The commonest presenting symptom is pain followed by dysphagia [5].

The current case was a 57 years old female patient presented clinically with history of a sore throat and right sided neck swelling and she was referred back to OPD at Damanhour Medical Institute (General Organization for teaching Hospitals & Institutes). Clinical examination revealed a necrotic ulcer replacing her right palatine tonsil and associated right sided cervical lymphadenopathy. Examination was otherwise normal. The ulcer was biopsied by an ENT surgeon. Histopathological examination revealed malignant melanoma. A pagetoid growth pattern with cytological atypia is noted, with enlarged cells containing large pleomorphic hyperchromic nuclei with prominent nucleoli. Numerous mitotic figures were also noted (see Figure:1).

Discussion:
Mucosal lentiginous melanomas (MLMs) develop from the mucosal epithelium that lines the respiratory, gastrointestinal, and genitourinary systems. These lesions account for approximately 3% of the melanomas diagnosed annually and may occur on any mucosal surface, including the conjunctiva, oral cavity, esophagus, vagina, female urethra, penis, and anus [2,5&6]. Noncutaneous melanomas commonly are diagnosed in patients of advanced age. When compared to cutaneous melanomas, MLMs appear to have a more aggressive course, although this may be because they commonly are diagnosed at a later stage of disease than the more readily apparent cutaneous melanomas [7]. Malignant melanoma may present in the tonsil either as a primary mucosal lesion or as a metastasis from a cutaneous malignant melanoma [8]. Both primary and metastatic malignant melanoma of the tonsil are extremely rare and it is important to differentiate between them [9]. Only 24 cases of metastatic melanoma of the tonsil have been reported [1]. Primary mucosal melanoma is commoner than metastatic disease and has a different site of predilection, mainly the oral cavity and the nasal cavity followed by the paranasal sinuses. Distinguishing between primary and metastatic malignant melanoma can be difficult and detailed histological examination is required. A history of previous malignant melanoma is helpful but multiple primary lesions may occur. Melanocytes are normally present in head and neck mucosal surfaces [12]. The most important histological pointer of a primary tumor is the presence of an intraepithelial neoplastic component (junctional cavity) in the overlying or adjacent lateral mucosa [13]. Although immunohistochemical stains usually are not necessary for diagnosis, they are generally performed for completeness. Both S-100 and homatropine methylbromide (HMB45) stains are positive in melanoma. The S-100 is highly sensitive, although not specific, for melanoma, while the HMB45 is highly specific and moderately sensitive for melanoma. The 2 stains, in concert, can be useful in diagnosing poorly differentiated melanomas [2]. Malignant melanoma metastasizes via lymphatic and vascular channels involving regional lymph nodes early on in the disease. Spread, via the systemic circulation or Batson's paravertebral venous plexus (low pressure system allowing retrograde spread) may account for involvement of the tonsillar region [10]. If a metastatic malignant melanoma is discovered, it is essential to make a careful clinical search for the primary lesion [14]. The appearance of a metastasis in the upper aerodigestive tract usually heralds widespread dissemination of the melanoma and a poor prognosis [5&15].

References:
1. Margolin KA, Sondak VK: Melanoma and other skin cancers. In: Cancer Management: A Multidisciplinary Approach. 4th ed. 2000: 431-59.
2. Wendy B & Burgress R Malignant Melanoma, September 8; 2003. eMedicine - Malignant Melanoma [http://www.emedicine.com/].
3. Sood SB, Nair SB, Fenwick JD, Horgan K. Metastatic melanoma of the tonsil. Journal of Laryngology and Otology 1999;113:1036-1038
4. Bradford CR, Futran N, Peters G: Management of tonsil cancer. Head Neck 1999 Oct; 21(7): 657-62
5. Sellars SL. Metastatic tumours of the tonsil. Journal of Laryngology and Otology 1971;85:289-292
6. Lisa T Galati: Malignant Tumors of the Tonsil , July 26, 2001; eMedicine - Malignant Tumors of the Tonsil Article by Lisa T Galati, MD.htm [http://www.emedicine.com/].
7. Henderson LT, Robbins KT, Weitzner S. Upper aerodigestive tract metastases in disseminated malignant melanoma. Archives of Otolaryngology - Head and Neck Surgery 1986; 112:659-663 8. Myers CM, Wood MD, Donegan JO. Metastatic melanoma to the palatine tonsil. ENT Journal 1983;62:538-539
9. Jackson SM, Hay JH, Flores AD, et al: Cancer of the tonsil: the results of ipsilateral radiation treatment. Radiother Oncol 1999 May; 51(2): 123-8[Medline].
10. Murphy D & Gillen P : Metastatic Melanoma of the tonsil. IMJ 2001 September; 94(8)
11. Wang MB, Kuber N, Kerner MM, et al: Tonsillar carcinoma: analysis of treatment results. J Otolaryngol 1998 Oct; 27(5): 263-9
12. Xavier R, Paiva A, Ribeiro da Silva P, Gameira dos Santos, A. Primary malignant melanoma of the palatine tonsil. Journal of Laryngology and Otology 1996;110:163-166
13. Ramamurthy L, Nassar WY, Hasleton PS. Metastatic melanoma of the tonsil and nasopharynx. Journal of Laryngology and Otology 1995;109:236-237
14. Batson OV. The function of the vertebral veins and their role in the spread of metastasis. Annals of Surgery 1940;112:138-153
15. Buzaid AC, Anderson CM: The changing prognosis of melanoma. Curr Oncol Rep 2000 Jul; 2(4): 322-8


FIGURE (1): MALIGNANT MELANOMA OF THE TONSIL

 

© Copyright of articles belongs to the respective authors unless otherwise specified.Verbatim copying, redistribution and storage of this article permitted provided no restrictions are imposed on the access and a hyperlink to the original article in Calicut Medical Journal maintained. All opinion stated are exclusively that of the author(s).
Calicut Medical Journal upholds the policy of Open Access to Scientific literature.