Malignant melanoma of gingiva: Case report and review of the literature :[PAUTHORS], Journal of Oral and Maxillofacial Pathology (JOMFP)

CASE REPORT
Year : 2022 | Volume : 26 | Issue : 4 | Page : 568--571

Malignant melanoma of gingiva: Case report and review of the literature

Pooja Sinha¹, Amrita Jayaswal², Abhishek Sinha³, Rohit Jaiswal⁴,
¹ Department of Public Health Dentistry, Sardar Patel Post Graduate Institute of Dental and Medical Sciences, Lucknow, Uttar Pradesh, India
² Prosthodontics and Crown & Bridge, Sardar Patel Post Graduate Institute of Dental and Medical Sciences, Lucknow, Uttar Pradesh, India
³ Oral Medicine & Radiology, Sardar Patel Post Graduate Institute of Dental and Medical Sciences, Lucknow, Uttar Pradesh, India
⁴ Oral Pathology & Microbiology, Sardar Patel Post Graduate Institute of Dental and Medical Sciences, Lucknow, Uttar Pradesh, India

Correspondence Address:
Amrita Jayaswal
Department of Prosthodontics and Crown & Bridge, Sardar Patel Post Graduate Institute of Dental & Medical Sciences, Lucknow - 226 025, Uttar Pradesh
India

Abstract

Mucosal malignant melanoma arising from the head and neck region is a rare entity, and it is more aggressive than cutaneous melanoma. Furthermore, the complexity of the oral cavity makes surgical excision more difficult. Oral malignant melanoma is a rare tumour of melanocytic origin, accounting for 20–30% of malignant melanomas at the mucosal surface and 16% intra-orally. Hard palate and maxillary gingiva are the most common involved sites. The age of reported patients ranges from 20 years to 80 years. Hence, we do hereby present a case of malignant melanoma of mandibular gingiva with review of the literature in a 42-year-old female patient.

How to cite this article:
Sinha P, Jayaswal A, Sinha A, Jaiswal R. Malignant melanoma of gingiva: Case report and review of the literature.J Oral Maxillofac Pathol 2022;26:568-571

How to cite this URL:
Sinha P, Jayaswal A, Sinha A, Jaiswal R. Malignant melanoma of gingiva: Case report and review of the literature. J Oral Maxillofac Pathol [serial online] 2022 [cited 2023 Mar 29 ];26:568-571
Available from: https://www.jomfp.in/text.asp?2022/26/4/568/364828

Full Text

Introduction

Oral malignant melanoma (OMM) was first introduced by Weber in 1859.[1] It is an extremely rare neoplasm arising from the uncontrolled growth of melanocytes found in the basal layer of the oral mucous membranes.[1],[2] These are derived from neural crest cells that migrate to the skin, mucous membranes, and many other sites whose function in the mucosa is not yet to be fully understood, but histologically, their presence along the rete ridges is well established. There is variation in the presence of melanocytes in different parts of the body and mucosal epithelium, for example, the ratio of melanocytes to basal keratinocytes. The ratio of melanocytes to keratinocytes in the oral epithelium's stratum basale ranges from 1:10 to 1:15. The cytologic appearance, organisation, and biologic characteristics of melanocytes, nevus cells, and melanoma cells are highly different. These cells are round- to spindle-shaped and may demonstrate some features of nevus cells such as the lack of dendritic processes and loss of contact inhibition. These malignant cells are pleomorphic, with large, irregular hyper-chromatic nuclei, prominent nucleoli, and conspicuous mitotic activity.[3] The clinical presentation of this condition may vary widely, which is divided into the following five types: pigmented nodular type, pigmented macular type, pigmented mixed type, non-pigmented nodular type, and non-pigmented mixed type.[2],[4],[5] Non-pigment forms of malignant melanoma often cannot be distinguished clinically from other benign or malignant oral tumours which can be diagnosed through biopsy. A pigmented lesion of the oral cavity should be viewed with suspicion because it does not possess clinical specificity.[6] This article reports a case of OMM of the maxillary anterior gingiva with cervical lymph node metastasis, which has been discussed with detailed investigations such as biochemistry, histopathology, ultrasound, and contrast-enhanced computed tomography (CECT) to emphasise the necessity for early diagnosis and treatment of this deadly condition.

Case Report

A 42-year-old female patient visited the Department of Oral Medicine and Radiology. The female patient [Figure 1] reported with the chief complaint of a painless, pigmented growth in the lower front tooth region since 5 months, which started as a pin point lesion, progressed gradually, and extended to the lower vestibular region. She gave no history of any systemic illness or trauma to the head and neck region. General physical examination was insignificant, and her vital signs were under normal limits.{Figure 1}

Extra-oral examination revealed a solitary left submandibular lymph node which was palpable, tender, and firm and fixed to the lower border of the mandible [Figure 2]. A solitary submental lymph node was also palpable in the left side, which was freely mobile, firm, and tender. On intra-oral examination, a pigmented growth was present in the mandibular region involving the attached and marginal gingiva extending bilaterally from 31 to 38 and from 41 to 45 and about 8 × 4 cm in size approximately [Figure 3]. This pigmented lesion extended lingually involving the gingival region from 31 to 38 and from 41 to 45. The lesion on the buccal aspect presented as a soft tissue growth which was black in colour extending superiorly involving the inter-dental papillae and inferiorly extended up to the buccal and labial vestibule. An area of fissuring was present in relation to 31 to 33. The lesion on the lingual aspect was flat and extended superiorly up to the marginal gingiva and inter-dental papilla and inferiorly up to the lingual vestibule. The bilateral extension was from 34 to 46 [Figure 4]. On palpation, the lesion was non-tender and soft in consistency. There was slight bleeding on provocation in the region of fissuring. Because the swelling was progressively increasing in size and was pigmented black in colour, the provisional diagnosis of malignant melanoma was made and differential diagnosis of melanosis, amalgam tattoo, drug-induced pigmentation, mucosal nevus, melanotic macule, and melano acanthoma was made. The patient was subjected to orthopantomogram (OPG) [Figure 5], and a complete blood cell count, biochemical analysis, and urine analysis were performed, which were insignificant and under normal limits. OPG revealed no bony changes in relation to the involved area. Considering the gravity of situation, an incisional biopsy was performed and the tissue was sent for histopathological diagnosis in 10% formalin. The section showed a para-keratinized stratified squamous epithelium with the underlying connective tissue stroma. The connective tissue showed atypical melanocytes and melanin pigmentation throughout the stroma. Dysplastic features such as cellular atypism and anisocytosis were seen in the connective tissue stroma with a mixed type of cells with downward invasion into the connective tissue, suggestive of malignant melanoma [Figure 6]. A few areas of the section showed large polyhedral cells with an eosinophillic cytoplasm and sometimes exhibiting fusiform and mixed types of cells with downward invasion into the connective tissue. Later, the section was subjected to immunohistochemical analysis, where the typical melanoma was found to be reactive for S 100 [Figure 7], protein, and melan A [Figure 8], which showed diffuse positivity in tumour cells. Based on the clinical examination and radiologic and histopathologic features, the final diagnosis of malignant melanoma was given.{Figure 2}{Figure 3}{Figure 4}{Figure 5}{Figure 6}{Figure 7}{Figure 8}

Later, the family was informed regarding the diagnosis, staging, and prognosis of disease.

Discussion

OMM accounts for 5% of all oral malignancies. It is a rarer aggressive neoplasm usually found on the hard palate and gingiva and was in accordance to our findings where lesion was seen in mandibular gingiva. The etiology is unknown, but tobacco and chronic irritation are suggested as probable causative factors. Over 30% of the cases have been reported to arise from pre-existing pigmented lesions. However, they are rare and estimated to represent 1–2% of all oral malignancies and account for about 0.2% to 8% of all melanomas.[7],[8] In various studies, the highest incidence of malignant melanoma is reported in the fifth decade of life (40–70 years).[9],[10],[11],[12],[13] Many reported cases of Malignant melanoma were found to be in middle age group with an age range of 22-83 years. Males appear to be more often affected with OMM than females, but in our case, the patient was a 40-year-old female. The clinical colouration of oral melanomas has a wide range, which can appear as black, grey, purple, and even reddish, which was very much in accordance to our findings, where the lesion was grey black in colour. Umedaa et al. described three growth phases of OMM: (1) a macular phase consisting of proliferation of dendrite melanocytes without apparent atypia and with simple hyper-pigmentation in the basal cell layer and incontinence,(2) a pigmented plaque phase consisting of pre-invasive tumour cell nests in the lower epithelial layer, and (3) a nodular phase consisting of spindle-shaped or epithelloid tumour cells in the submucosa.[4],[13] Histologically, it resembles squamous cell carcinoma, with large polyhedral cells with an eosinophillic cytoplasm and sometimes exhibiting fusiform and mixed types of cells with downward invasion into the connective tissue.[13] Immunohistochemically, the typical melanoma is reactive for vimentin, S-100, protein, HMB-45, melan-A, tyrosinase, and micropthalmia transcription factor 14 OMMs are rarer but aggressive tumours with very low survival rates which can metastasize rapidly. Owing to its rarity, all pigmented lesions in the oral cavity should be examined with suspicion. The treatment of choice for oral melanomas is wide surgical resection with or without neck dissection depending upon chemotherapy as an adjuvant or palliative therapy. However, close patient monitoring is imperative to check for recurrence. Hence, the purpose of this case report was to emphasize on early diagnosis and to maintain a high index of suspicion for those pigmented lesions occurring in the high risk sites such as palate and maxillary gingiva. The poor prognosis of OMM has a 5-year survival rate between 15% and 38%.[14] Metastasis from OMM occurs to the regional lymph nodes and in such distant sites as the lung, liver, brain, and bone with recommended chest x-ray and pet scan after every 6 months. Post-surgery is a necessary tool to assess distant metastasis, but in our case, the patient did not respond after surgery.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Acknowledgement

Our sincere thanks to Dr. Pratibha Ramani Professor and Head Department of oral and maxillofacial Pathology for her help in hitopathological evaluation and special staining done for the diagnosis of the case.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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