Authors: Nanayakkara PR*, Arudchelvam JD** Ariyaratne JC*, Mendis K*, Jayasekera KAMP***
*Senior Registrar in Surgical Oncology, **Registrar in Surgery, ***Consultant in Surgical Oncology
Institution: The National Cancer Institute, Maharagama, Sri Lanka
Dr. P.R. Nanayakkara MBBS MD MRCS
92/22, Thalapathpitiya road,
Udahamulla, Nugegoda, Sri Lanka.
Oral cavity melanomas are very rare and they carry a poor prognosis. Prophylactic ipsilateral cervical lymph node dissection offers better control of regional disease, although survival is not affected. We describe a sixty year old male who presented with cervical lymph node metastasis from a malignant melanoma of the tongue.
Malignant melanoma of the oral cavity is a rare disease and has a poor prognosis. When it involves the oral cavity, the palate and gingiva are most commonly affected. This article describes a case of malignant melanoma that involved the ventral surface of the tongue.
A sixty year old male presented to a general hospital with a history of a black colored patch to the right of the midline on the inferior surface of tongue, for 1 month duration. It was painless, progressively increasing in size and bled occasionally when traumatized. There were no similar lesions within the oral cavity or elsewhere on the body. Fine needle aspiration cytology (FNAC) confirmed malignant melanoma. A wide local excision of the lesion was carried out. The patient recovered with mild slurring of speech. Histopathology revealed an epitheliod malignant melanoma with surface ulceration. Clarks’ level was IV with a Breslow thickness of 5.1 mm. The tumor was in a vertical growth phase with pagetoid spread of melanoma cells into the epidermis. Since the margin of clearance was considered inadequate, a wider excision was done with pathologically confirmed clear margins. However, a prophylactic cervical nodal dissection was not carried out.
A month later, the patient noticed a lump on the right side of the neck. FNAC of the lump revealed pigment laden atypical cells, consistent with metastasis from a malignant melanoma. The patient was then referred to our unit for further management. Contra-lateral cervical nodal, pulmonary and hepatic involvements were excluded by a metastatic workup. A type I modified radical cervical block dissection was performed. Intra-operatively, black colored enlarged lymph nodes were found from level I to level V. The patient made an uneventful recovery.
Subsequent histopathology revealed metastatic deposits of malignant melanoma in 16 out of 22 lymph nodes (level I - IV). Neoplastic cells were positive for S-100 and HMB-45 immune markers. The patient was thereafter referred to an oncologist for follow up. Click on The Pictures Below to Enlarge
Figure 1. The tip of the forceps points to a blackish lymph node at level Ib near the right submandibular gland.
Figure 2. The tip of the forceps points to another suspicious lymph node at level III near the divided internal jugular vein.
Mucosal melanomas are a rare entity and oral cavity melanomas are even rarer, representing 1-2% of all oral malignancies.1 Melanoma of the oral cavity accounts for about 0.2–8% of all malignant melanomas.2 Oral melanomas most frequently involve the maxillary gingiva and palate with the lip being the third most common site.2 Melanoma of the tongue represents less than 2% of all oro-nasal malignant melanomas.2 A review of literature revealed less than 30 cases of primary malignant melanoma of the tongue, with the earliest reference appearing in a survey article by Baxter3 in 1941.
With an equal sex incidence, oral melanomas commonly occur after the 5th decade of life.1 They present as flat, painless, dark brown or black, discolored macules or nodules, sometimes with erythema or ulceration. Less than 10% of oral melanomas are amelanotic. Histologically, oral melanomas are characterized by the presence of atypical melanocytes that are larger than the usual melanocytes with nuclear pleomorphism and hyperchromatism, in abundance.1 Immunohistochemistry profile of oral melanoma is similar to that of cutaneous melanoma,2 with the exception that the former is negative for cytokeratin. Our patient’s lesion was positive for S-100 protein and HMB-45 stains.
Surgery is the mainstay of treatment for melanomas. Wide local excision with a margin of 2-5 cm is necessary for cutaneous melanoma but it is difficult to achieve this in oral melanomas due to anatomical restrictions especially in the head and neck region. Sentinel lymph node biopsy was not initially performed since the patient had a late stage mucosal melanoma with an initial tumor thickness greater than 4 mm and a high risk of distant metastasis. Sentinel lymphnode biopsy has not been shown to be of benefit in this group of patients.
Radiotherapy is often recommended in the postoperative management of mucosal melanomas due to this reason. Retrospective studies in mucosal melanomas show lower local and regional recurrence rates after using postoperative radiation. Dacarbazine and Interferon-α have been described as chemotherapeutical and immunotherapeutical agents useful in the treatment of melanomas.1 Our patient was treated with Interferon-α after cervical block dissection.
Since the likelihood of positive regional disease is significantly higher in patients with a mucosal melanoma, the ipsilateral neck can be treated with both surgery and radiation.5 Our patient was not offered a prophylactic ipsilateral neck dissection at the time of excision of the primary.
The authors of this article recommend a prophylactic ipsilateral neck dissection for oral cavity mucosal melanoma along with the treatment of the primary at the same sitting, for control of local and regional disease.
Mucosal melanomas carry a poor prognosis, even with a limited primary burden of disease. Thus, the AJCC staging system for mucosal melanoma begins with stage III disease as the most limited form of disease.6 Oral melanomas have a poorer prognosis than cutaneous melanomas with the five year survival rate of only 11-18%.1
Since late diagnosis results in advanced disease with recurrences and metastases, a high index of suspicion, careful oral examination and prompt biopsy is recommended.
1. Hashemi Pour MS. Malignant melanoma of the oral cavity: A review of literature. Indian Journal of Dental Research. 2008; 19(1):47-51. View Article
2. Khalifa H, Abdullah S, Sallam K, Khalil H, Moneim IA, Elaffandi A. Primary malignant melanoma of the tongue. Can J Surg. 2009 Dec;52(6):E309-11. View Abstract
3. Baxter, H. A review of malignant melanoma of the mouth - Report of a case. American Journal of Surgery. 1941; 51:379-386.
4. Owens JM, Roberts DB, Myers JN. The role of postoperative adjuvant radiation therapy in the treatment of mucosal melanomas of the head and neck region. Arch Otolaryngol Head Neck Surg. 2003 Aug;129(8):864-8. View Abstract
5. National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology. Head and Neck Cancers. 2010. View Article
6. Edge S, Byrd D, Compton C, et al.; eds. American Joint Committee on Cancer Staging Manual, 7th edition. New York: Springer; 2010.