Primary Oral Mucosal Melanoma Research Articles

Primary Malignant Melanoma of the Oral Mucosa

To present our experience on the epidemiology, clinical features, management, and survival of patients with oral malignant melanoma. Records of patients with a histologic diagnosis of primary oral mucosal malignant melanoma seen over a 23-year period were retrospectively reviewed. There were 6 females and 2 males, ranging in age from 18 to 60 years; 4 cases in the maxilla, 2 in the mandible, 1 on the lower lip, and 1 on the buccal mucosa. Local recurrences developed in 2 patients who eventually died with clinical metastatic cervical nodal disease. Follow-up ranged from 6 months to 16 years 3 months. Surgery was the only treatment available. Primary oral mucosal melanoma is rare, with a 3 to 1 female to male ratio and an average age of 41.7 years at presentation. It is most common in the maxilla and has poor prognosis despite apparent adequate local surgical control.

Wnt5a Overexpression in Thick Primary Oral Mucosal Melanomas:

Wnt genes encode a large family of secreted cysteine-rich signaling molecules involved in cell growth, differentiation and tumorigenesis. Wnt5a, a non-transforming member of the Wnt family behaves as a putative oncogene in many cancers including melanomas. The aim of our study was to determine Wnt5a expression in primary oral mucosal melanomas (OMM) and correlate it with tumor thickness. Archival tissues from 18 OMM cases were subjected to immunohistochemical detection of Wnt5a by the streptavidin-biotin method. These were categorized into tumors of 4 mm (thick lesions) thickness. Most OMM cases (17/18; 94.4%) stained positive for Wnt5a, though heterogeneously. Seven thick (7/11; 64%) and one intermediate thickness (1/7, 14%) OMM demonstrated strongly positive Wnt5a staining (P<0.05). The only Wnt5a-negative case was a thick OMM without local recurrence after treatment. Strong Wnt5a expression at tumor advancing sites suggests a role in local tumor spread. Identification of pleomorphic epithelioid and spindle cells as melanoma cell populations with the most pronounced Wnt5a staining suggests that Wnt5a overexpression influences cellular phenotype. These results taken together suggest that Wnt5a is up-regulated in OMM and may play a role in tumor progression.

HMB‐45 may be a more sensitive maker than S‐100 or Melan‐A for immunohistochemical diagnosis of primary oral and nasal mucosal melanomas

Primary mucosal melanomas (MMs) of the head and neck are a rare entity. Melanomas with characteristic melanin-pigmented tumor cells are easy to diagnose, but those without melanin-pigmented tumor cells, amelanotic melanomas, are difficult to identify and need immunohistochemistry (IHC) to confirm the final diagnosis. In this study, we examined the expression of three melanocytic differentiation markers, HMB-45, S-100, and Melan-A in primary oral and nasal MMs. We tried to evaluate whether HMB-45, S-100, and Melan-A were useful for diagnosis of primary oral and nasal MMs and to find out which marker was the best of the three. This study used IHC to examine the expression of HMB-45, S-100, and Melan-A in 17 formalin-fixed paraffin-embedded specimens of primary oral and nasal MMs. The staining intensities (SIs) and labeling indices (LIs) of HMB-45, S-100, and Melan-A in 17 MMs were calculated and compared between any two markers. Immunostaining results showed that the positive rate was 94% (16 of 17) for HMB-45, 88% (15 of 17) for S-100, and 71% (12 of 17) for Melan-A in 17 MMs. The SI of HMB-45 was significantly higher than that of S-100 (P = 0.0011) or of Melan-A (P = 0.0034). In addition, the mean LI of Melan-A (59 +/- 43%) was significantly lower than that of HMB-45 (83 +/- 28%, P = 0.0065) or of S-100 (79 +/- 33%, P = 0.0237). Our results indicate that both HMB-45 and S-100 show a high positive rate and LI in MMs and therefore may be good markers for immunohistochemical diagnosis of primary oral and nasal MMs. In addition, HMB-45 may be a more sensitive marker than S-100 because HMB-45 shows a significantly higher SI than S-100 in this study.

PRIMARY MALIGNANT MELANOMAS OF THE ORAL CAVITY IN PAPUA NEW GUINEA

The aims of this paper are to review the incidence and pathology of primary oral mucosal melanomas in Papua New Guinea and describe the presentation and management of five cases.

A clinicopathological and immunohistochemical analysis of primary oral mucosal melanoma.

Nine cases of primary oral mucosal melanoma in Caucasian patients were reviewed and the tumours analysed for expression of S100, HMB45, NKI/C3, HLA-DR, PCNA, cytokeratin and von Willebrand factor. The clinical, histopathological and immunohistochemical features were quite distinctive and our findings support previous suggestions that oral melanoma should be classified as a separate entity rather than as a sub-type of cutaneous melanoma.

Immunohistochemical localization of S‐100 protein and its subunits in melanotic lesions in the oral mucosa and skin

Immunohistochemical localization of S-100 protein, S-100 alpha and beta subunits was examined in 23 pigmented nevi, 20 malignant melanomas and 8 metastatic melanomas originating from the oral mucosa and skin. Primary oral mucosal melanomas demonstrated no beta subunit immunoreactivity while one metastatic lesion from oral melanoma that showed only a small number of melanoma cells reacted with the beta subunit. In contrast, most cutaneous melanomas and their metastatic lesions showed immunoreaction with the S-100 beta subunit. As for pigmented nevi, immunoreactions with the three antibodies were frequently detected regardless of the site. The differences in the expression of S-100 protein beta subunit between cutaneous and mucosal melanomas may be related to differences in inductive interactions between the melanoma cells and the connective tissues and skin and mucosa.