primary malignant melanoma of the tongue

764Case Report

Primary malignant melanoma of the oral cavity isa rare neoplasm. The incidence of oral cavity

melanoma is about 0.2% to 8% of all malignantmelanoma cases.(1) Primary lesions arising from oralmucosa occur most frequently on the maxillary gin-giva and palate, with the lips following as the thirdmost common in frequency. Melanoma of thetongue is specifically uncommon and represents lessthan 2% of all oro-nasal melanoma cases.(2) Areview of the literature revealed fewer than 30 casesof primary malignant melanoma of the tongue hadbeen reported and a tumor size of more than 6¡ 5 cmwas even more unusual as discovered in our review.

CASE REPORT

A 66-year-old woman was referred to our clinicwith the complaint of a painless mass on the rightside of the oral tongue. She had been aware of thedark discolored mass for 7 years; however, it gradu-ally increased in size within the past 6 months. Onexamination, a black, pigmented and ulcerated massmeasuring approximately 6¡ 5 cm in size was foundon the right side of the tongue with floor extension(Fig. 1). There were no cutaneous lesions suggestiveof malignant melanoma over the rest of her body.The biopsy of the tongue lesion revealed ahistopathology consistent with primary malignant

Primary Malignant Melanoma of the Tongue

Tien-Tse Chiu, MD; Hsin-Ching Lin, MD; Chih-Ying Su, MD; Chao-Cheng Huang1, MD

The oral cavity is a rare location for the development of primary malignant melanoma.The most common primary lesion sites are the palate and gingiva. Melanoma of the tongueis specifically uncommon. A 66-year-old woman was referred to our clinic with a complaintof a huge, painless, black, discolored mass on the right side of the oral tongue for 7 years.There were no cutaneous lesions suggestive of malignant melanoma over the rest of herbody. The biopsy of the tongue lesion revealed a histopathology consistent with primarymalignant melanoma. Computed tomography of the neck showed no significant cervicallymphadenopathy. Chest radiograph, whole body bone scanning, and abdominal sonogra-phy revealed no definite distal metastatic lesions. She received composite resection of thetumor on the right side of the tongue and right functional neck dissection. The patient hadan uneventful recovery and received regular follow-up examinations. She was free of dis-ease for more than 2 years. The treatment principle for primary tongue melanoma is widesurgical excision. Early diagnosis will be promoted by careful oral examination and earlybiopsy of pigmented and non-pigmented masses. We reviewed the published reports in theEnglish literature since 1970 and fewer than 30 cases of primary tongue melanoma werepresented. We present a case report and a review of the relevant literature. (Chang GungMed J 2002;25:764-68)

Key words: malignant melanoma, tongue.

From the Department of Otolaryngology, 1Department of Pathology, Chang Gung Memorial Hospital, Kaoshung; Chang GungUniversity, Taoyuan.Received: Oct. 29, 2001; Accepted: Feb. 28, 2002Address for reprints: Dr. Chih-Ying Su, Department of Otolaryngology, Chang Gung Memorial Hospital. 123, Ta-Pei Road,Niaosung 833, Kaoshung, Taiwan, R.O.C. Tel.: 886-7-7317123 ext. 2533; Fax: 886-7-7318762; E-mail: [email protected]

Chang Gung Med J Vol. 25 No. 11November 2002

Tien-Tse Chiu, et alMalignant melanoma of the tongue

765

melanoma. Computed tomography of the neckshowed a right anterior lateral tongue mass with highintensity after contrast enhancement (Fig. 2). Therewas no significant cervical lymphadenopathy. Chestradiograph, whole body bone scanning and abdomi-nal sonography revealed no definite distant metastat-ic lesions. She received a composite resection of the

tumor on the right side of her tongue and right func-tional neck dissection. The histopathological find-ings revealed a malignant melanoma characterizedby neoplastic proliferation of epithelioid to spindlemelanocytes with melanin deposits and underlyingskeletal muscle invasion. Scattered tumor cell nestswere also present in the overlying squamous epitheli-um, suggesting that the tumor was a primary ratherthan a metastatic lesion (Fig. 3). The resection mar-gin and base of the tumor were clear and no evidenceof metastasis was found in the tissue of the function-al neck dissection. The patient had an uneventfulrecovery and received regular follow-up examina-tions. She has been free of disease for more than 2years, with no clinical or biochemical evidence ofmetastasis.

DISCUSSION

The mucosal membranes are rare sites for pri-mary malignant melanoma. The presence ofmelanocytes in the mucosal membrane of respiratory,alimentary and urogenital tracts explains the occur-rence of malignant melanoma in these sites.(3)

Melanoma of the oral cavity mucosa is a distinctly

Fig. 1 A black, pigmented and ulcerated mass measuringapproximately 6¡ 5 cm was found on the right side of thetongue with floor extension.

Fig. 2 Computed tomography of the neck showed a rightanterior lateral tongue mass with high intensity after contrastenhancement.

Fig. 3 Histopathlogical findings of malignant melanoma. Thetumor presents as a protruding mass composed of sheets ofepithelioid to spindle-shaped neoplastic melanocytes. Thetumor cells arranged in whorling fascicles or nests with focalmelanin deposition. There are also scattered tumor cell nestsnoted in the squamous epithelium (arrows) (H&E, 100¡ ).



766

rare occurrence with an incidence of 0.012/105 forcombined primary and metastatic lesions to oral cav-ity.(2) The tumors are commonly found in patientsolder than 40 years and there are no significant dif-ferences between genders.(2,4,5) The oral cavity maybe a site of predilection for melanomas inJapanese,(4,6) although it is very rare in the white pop-ulations.(7) We reviewed the reports in the Englishliterature and fewer than 30 cases of primary malig-nant melanoma of the tongue were found. Men weremore commonly affected than women in primarymalignant melanoma of the tongue which was incontrast to skin melanoma where the incidencebetween genders was roughly equal.

Oral pigmentation preceded the development ofmalignant melanoma in about a third of thepatients.(8) Takagi et al. reported that mucosalmelanosis was associated in 66% of oral melanoma,pre-existing in 36.2% and concurrent in 29.8%.(6)

There are many situations to be considered in theclinical differential diagnosis: Tattoos, melanoticmacules, Laugier's disease, melanocytic nevus, drugintake, some vascular lesions, and oral pigmentedlesions associated with endocrine disorders or differ-ent syndromes.(9) Our patient had had the oral darkpigmentation for 7 years, but she did not pay muchattention to it. We suggested that a deep biopsyshould be performed on any intra-oral pigmentedlesions with the tendency of malignant transforma-tion.

Oral melanomas may present as flat, painless,dark brown or black discoloration macules or nod-ules, sometimes with erythema or ulceration. As thedisease progresses, bony erosion is common. A veryimportant point in the management of malignantmelanoma of the oral cavity is to exclude the possi-bility of it being a metastasis from a cutaneousmelanoma. This is because metastasis plays a largerole in determining the goals and method of treat-ment. In the histopathologic distinction, Billings etal. found that all metastatic lesions lacked evidenceof junctional activity in the overlying mucosa andshowed no epidermal migration. This is in contrast toprimary lesions, in which 44 % and 38% had junc-tional activity and epidermal migration, respectively.A unique feature seen in the primary lesions (25%)was the presence of extensions of the melanotic pig-ment into the minor salivary glands.(10) However,these findings may be inconsistent, and the diagnosis

of a primary oral mucosal melanoma requires thecareful search for and exclusion of any suggestedcutaneous or mucosal lesions.(11) For this patient,there was no history of melanoma-like lesion exci-sion. We did not find any cutaneous lesions sugges-tive of malignant melanoma over her body, extremi-ties, head or neck; there were not any pigmentedlesions in the nasal cavity, pharynx and larynx. Thehistopathological findings revealed scattered tumorcell nests that were also present in the overlyingsquamous epithelium, suggesting that the tumor wasa primary rather than a metastatic lesion. Physicalexamination and histopathologic findings suggestedthe diagnosis of primary melanoma.

The immunohistochemical profile of oral malig-nant melanoma was similar to that of cutaneousmelanoma, with the exception that no oral malignantmelanoma was positive for cytokeratin.(12) HMB-45are regarded as showing greater specificity formelanoma than S-100 protein.(13) The immunoperox-idase stains of our patient showed positive finding inS-100 protein and HMB-45 stains.

Surgery is believed to be the most effectivetreatment for melanoma.(1) Wide resection with asurgical margin 2 to 5 cm is necessary for cutaneousmelanoma, but is difficult to achieve for oralmelanoma because of anatomical reasons. Ourpatient received a composite resection of the tumoron the right side of the tongue and right functionalneck dissection. The histopathological findingsrevealed no evidence of metastasis and the resectionmargin was clear. A series of studies showed no evi-dence of distal metastasis. The role of radiotherapyis controversial because many authors believemelanoma to be a radioresistant neoplasm, and it isfrequently used for palliation. Radiotherapy andchemotherapy play an important role in the primarymanagement of unresectable diseases. Because theresection margin was clear and no loco-regionalrecurrence or distant metastasis have been found tillnow, our patient do not received any radiation thera-py or chemotherapy. In recent years, immunologicaltherapies have been used. The most widely usedcytokines are interferons and interleukin-2.However, immunotherapy has not improved survivalor local regional control rates in patients with mucos-al melanoma.(14)

In general, the prognosis for patients with oralmalignant melanoma is poorer than that for patients



767

with cutaneous lesions. The 5-year survival rateswere 6.6% to 20%.(5,6,15) Several factors may con-tribute to this poor prognosis including lack of symp-toms early in the disease, difficulty in achieving wideradical excision because of anatomic limitations, andrich blood supply that may facilitate hematogenousspread.(2)

Early diagnosis will be promoted by careful oralexamination and early biopsy of pigmented and non-pigmented masses. Early diagnosis and treatmentwill improve the prognosis of patients with oralmalignant melanoma.

REFERENCES

1. Rapini RP, Golitz LE, Greer RO Jr, Krekorian EA,Poulson T. Primary malignant melanoma of the oral cavi-ty: A review of 177 cases. Cancer 1985;55:1543-51.

2. Chiu NT, Weinstock MA. Melanoma of oronasal mucosa:population-based analysis of occurrence and mortality.Arch Otolaryngol Head Neck Surg 1996; 122:985-8.

3. Gutman M, Inbar M, Chaitchik S, Merhav A, Pausner D,Skoznik Y, Ilie B, Rozin RR, Klausner JM. Malignantmelanoma of the mucous membranes. Eur J Surg Oncol1992;18:307-12.

4. Tanaka N, Amagasa T, Iwaki H, Shioda S, Takeda M,Ohashi K, Reck SF. Oral malignant melanoma in Japan.Oral Surg Oral Med Oral Pathol 1994;78:81-90.

5. Lopez-Graniel CM, Ochoa-carrillo FJ, Meneses-Garcia A.Malignant melanoma of the oral cavity: diagnosis andtreatment: Experience in a Mexican population. OralOncol 1999;35:425-30.

6. Takagi M, Ishikawa G, Mori W. Primary malignantmelanoma of the oral cavity in Japan: with special refer-ence to mucosal melanosis. Cancer 1974;34:358-70.

7. Manolidis S, Donald PJ. Malignant mucosal melanoma ofthe head and neck: review of the literature and report of14 patients. Cancer 1997; 80:1373-86.

8. Powell JP, Cummings CW. Melanoma and the differentialdiagnosis of oral pigmented lesions. Laryngoscope1978;88:1252-67.

9. Seoane Leston JM, Vazquez Garcia J, Aguado Santos A,Varela-Centelles PI, Romero MA. Dark oral lesions: dif-ferential diagnosis with oral melanoma. Cutis1998;61:279-82.

10. Billings KR, Wang MB, Sercarz JA, Fu YS. Clinical andpathologic distinction between primary and metastaticmucosal melanoma of the head and neck. OtolaryngolHead Neck Surg 1995;112:700-6.

11. Calabrese V, Cifola M, Pareschi R, Parma A, Sonzogni A.Primary malignant melanoma of the oral cavity. JLaryngol Otol 1989;103:887-9.

12. Barrett AW, Bennett JH, Speight PM. A clinicopathologi-cal and immunohistochemical analysis of primary oralmucosal melanoma. Oral Oncol, Eur J Cancer 1995;31B:100-6.

13. Leong ASY, Milios J. An assessment of a melanoma-spe-cific antibody (HMB45) and other immunohistochemicalmarkers of malignant in paraffin-embedded tissue. SurgPathol 1989;2:137-45.

14. Nandapalan V, Roland NJ, Helliwell TR, Williams EM,Hamilton JW, Jones AS. Mucosal melanoma of the headand neck. Clin Otolaryngol 1998;23:107-16.

15. Liversedge RL. Oral malignant melanoma. Br J Oral Surg1975;13:40-55.

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