Mucosal Melanoma In Situ of the Oral Cavity: A Case Report and Systematic Review of the Literature

Abstract

Objective: Malignant mucosal melanomas of the head and neck comprise a very small portion of all melanomas, particularly in the oral cavity. These lesions are associated with high rates of local recurrence, distant metastasis, and a very poor 5-year survival rate; however, the clinical outcomes of mucosal melanoma in situ of the oral cavity are unclear. Therefore, we present a case report of mucosal melanoma in situ and a systematic review of the literature to shed light on this rare but important disease.

Methods: PubMed, Scopus, and CINAHL were searched per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were only considered for inclusion if they described oral cavity melanoma in situ and documented specific data pertaining to treatment including modality, lesion size, or outcomes.

Results: A total of 28 reported cases from the literature fulfilled the inclusion criteria, as well as one case from our own institution. Men comprised the majority (64.3%) of the cases, and the average age at presentation was 57.4 years. The hard palate was the most common location, and most cases were treated with surgical excision. Eight had no evidence of disease after a minimum of six months of follow-up, one reported spread to the cervical lymph nodes, and only one reported progression with distant metastasis.

Conclusion: Oral mucosal melanoma in situ is a rare entity and most commonly treated with surgical excision. High rates of recurrence necessitate long term follow-up. Further studies may be useful to determine whether adjuvant therapy may play a role in reducing recurrence.

Keywords: Mucosal melanoma in situ; hard palate; management; oral cavity; systematic review.

Figure 1

Clinical presentation of lesion on left side of the floor of the mouth prior to surgical resection

Figure 2

Medium-power photomicrograph showing an irregular proliferation of atypical pigmented melanocytes along the basilar layer of the mucosal epithelium (Note: The melanin observed in the superficial lamina propria represents pigment incontinence, not tumor invasion)

Figure 3

Surgical site 12 months status post resection showing no evidence of disease

Figure 4

PRISMA diagram detailing database search procedure PRISMA: Preferred Reporting Items for Systematic Reviews and Meta- Analyses