Oral melanoma: diagnosis and treatment

Current Trends in Mucosal Melanomas: An Overview

Primary mucosal melanomas (MMs) are uncommon tumors originating from melanocytes located in the mucous membranes at various anatomic sites within the body. MM significantly differs from cutaneous melanoma (CM) regarding epidemiology, genetic profile, clinical presentation, and response to therapies. Despite these differences, that have important implications for both disease diagnosis and prognosis, MMs are usually treated in the same way as CM but exhibit a lower response rate to immunotherapy leading to a poorer survival rate. Furthermore, a high inter-patient variability can be observed in relation to therapeutic response. Recently, novel "omics" techniques have evidenced that MM lesions have different genomic, molecular, and metabolic landscapes as compared with CM lesions, thus explaining the heterogeneity of the response. Such specific molecular aspects might be useful to identify new biomarkers aimed at improving the diagnosis and selection of MM patients who could benefit from immunotherapy or targeted therapy. In this review, we have focused on relevant molecular and clinical advancements for the different MM subtypes in order to describe the updated knowledge relating to main diagnostic, clinical, and therapeutic implications as well as to provide hints on likely future directions.

Pevonedistat targeted therapy inhibits canine melanoma cell growth through induction of DNA re-replication and senescence

MLN4924 (pevonedistat) is a potent and selective NEDD8-activating enzyme (NAE) inhibitor. The NEDD8-regulated neddylation system is responsible for the regulated degradation of intracellular proteins with important cellular functions in cancer cell growth, apoptosis, angiogenesis and metastasis. In human melanoma, inhibition of NAE results in induction of DNA re-replication, S phase cell cycle arrest, DNA damage and apoptosis. The study aimed to assess the anti-cancer effect of MLN4924 on canine malignant melanoma cell lines and patient samples and to elucidate the underlying mechanisms. Canine melanoma cell lines and primary patient samples were evaluated for cell viability after incubation with varying concentrations of MLN4924 or dimethyl sulfoxide. Apoptosis, cell proliferation and senescence assays were performed to address underlying mechanisms of MLN4924-mediated anti-tumour effects. Gene expression of seven previously identified deregulated genes in human melanoma was compared in sensitive vs resistant samples. MLN4924 treatment significantly reduced the viability of canine melanoma cell lines and primary samples in a dose- and time-dependent manners. MLN4924 promoted cell apoptosis and inhibited cell growth through induction of DNA re-replication and cell senescence. While the majority of canine melanoma samples demonstrated sensitivity at nanomolar ranges, some samples were resistant to the treatment. Modulation of P21 levels correlated with canine melanoma cell sensitivity. These results provided justification for further exploration of MLN4924 as a treatment of canine melanoma.

The existence of early stage oral mucosal melanoma: A 10-year retrospective analysis of 170 patients in a single institute

BACKGROUND

Oral mucosal melanoma (OMM) is an aggressive tumor with an extremely low incidence, and the current TNM Staging System has classified all OMMs as high stage. However, controversy remains regarding the existence of early stage OMMs.

PATIENTS AND METHODS

The clinical and pathological features, treatments and outcomes of 170 OMM patients treated in a single institution from January 2007 to July 2017 were retrospectively analyzed. Multivariate analysis was performed to identify significant prognostic factors for overall survival (OS).

RESULTS

Multivariate analysis identified positive cervical lymph nodes (p < 0.0001), nodular OMMs (p < 0.0001), ulceration (p = 0.002), and level III or level IV invasion (p < 0.0001) as independent poor prognostic factors for OS. Nodular OMM patients with a tumor size ≤1 cm had a better outcome than those with a tumor size >1 cm (p < 0.0001). Twenty-two patients with superficial invasion had a favorable survival without the need of adjuvant therapy (postoperative chemotherapy or radiotherapy), and the current TNM Staging System was not suitable for those patients. Patients with deep invasion were more likely to suffer from recurrence and distant metastasis.

CONCLUSIONS

Tumor size ≤1 cm and OMM in situ, although extremely rare, do exist. It is advisable for AJCC to consider tumor size ≤1 cm and OMM in situ as the early stage of OMM when updating the new Oral Melanoma Staging System.

A rare case of amelanotic malignant melanoma in the oral region: Clinical investigation and immunohistochemical study

Amelanotic malignant melanoma (AMM) is rare in the oral region. The present study examined the clinical features of this tumor in an attempt to establish diagnostic criteria. The expression of three melanocytic differentiation markers, HMB-45, S-100 and Melan-A, was also measured in primary oral AMMs in order to determine whether the markers could be used to diagnose primary oral AMMs and to find out which marker was the most sensitive. It may be particularly difficult to correctly diagnose AMM that lacks a radial growth phase without immunohistochemical assistance. In the present study, mixtures of polygonal and spindle cells at different ratios were observed in the tumors with and without a radial growth phase. Immunohistochemistry was used to examine the HMB-45, S-100 and Melan-A expression in the formalin-fixed paraffin-embedded specimens of primary oral AMMs. Comparison of staining intensities (SIs) and labeling indices (LIs) of the markers was also performed. The immunostaining results revealed that the SI of Melan-A was significantly higher than that of S-100 (P=0.0011). HMB-45, S-100 and Melan-A also exhibited high positive rates and LIs in AMMs and, therefore, may be good markers for the immunohistochemical diagnosis of primary oral AMMs. Furthermore, Melan-A may be a more sensitive marker than S-100 and HMB-45, as it has a higher SI.

Oral malignant melanoma: A report of two cases with BRAF molecular analysis

Primary oral malignant melanoma is a rare condition, accounting for 1.3–1.4% of all melanomas, usually presenting with an aggressive clinical behavior. The present study reports the clinicopathological findings of two cases of oral malignant melanoma and discusses the epidemiology, diagnosis and current therapeutic approaches for this uncommon condition. In the first case the patient presented with a pigmented lesion located on the lower mucosal lip. The patient showed no nodal metastases and therefore, underwent a wedge resection. After seven months, the patient presented with neck lymph nodes and multiple visceral metastases. Molecular analysis of BRAF, using a pyrosequencing approach, revealed the presence of BRAF V600E mutation. The patient developed multiple visceral metastases, but refused treatment and was lost to follow-up. In the second case, no BRAF V600E mutation was found, but the patient exhibited a pigmented patch in the lower gingival mucosa, which was excised by surgical treatment. The patient was followed up by an oncologist, but did not undergo an additional therapy and is currently alive with no evidence of visceral metastases at one year following the diagnosis.

Mucosal melanomas in the elderly: challenging cases and review of the literature

Melanomas are malignant tumors that originate from melanocytes. They are most frequently localized in the skin, but 5% of all melanomas interest also extracutaneous sites as mucosal surfaces, parenchymatous organs, the retroperitoneum area, and the ocular ball. The purpose of this study was to investigate the epidemiologic and morphologic data of mucosal melanomas diagnosed at Emergency City Hospital (Timisoara, Romania) during a period of 12 years. The study included 17 cases of extracutaneous, extraocular melanomas, with 16 primary melanomas and one secondary melanoma. All our patients were older than 53 years and were mostly men. Most of the patients presented with localized disease; only one case had regional lymph node metastases, and another one had systemic metastases at the time of diagnosis. Regarding localization, nine of 16 melanomas were in the head and neck region, six were diagnosed in the gastrointestinal and urogenital tracts (three cases each), and one case had a rare localization (retroperitoneum). The most common histologic type was represented by epithelioid cells, and the majority of the tumors were achromic. Mucosal melanoma is a tumor associated with aging, all our patients being older than 53 years. Because of unspecific symptoms and low incidence, the diagnosis is often delayed and requires teamwork among the clinician, pathologist, radiologist, and oncologist. Different genetic fingerprints impose a correct diagnosis to offer the patient the best novel, personalized therapy.

Oral pigmented lesions: Clinicopathologic features and review of the literature

Diagnosis of pigmented lesions of the oral cavity and perioral tissues is challenging. Even though epidemiology may be of some help in orientating the clinician and even though some lesions may confidently be diagnosed on clinical grounds alone, the definitive diagnosis usually requires histopathologic evaluation. Oral pigmentation can be physiological or pathological, and exogenous or endogenous. Color, location, distribution, and duration as well as drugs use, family history, and change in pattern are important for the differential diagnosis. Dark or black pigmented lesions can be focal, multifocal or diffuse macules, including entities such as racial pigmentation, melanotic macule, melanocytic nevus, blue nevus, smoker’s melanosis, oral melanoacanthoma, pigmentation by foreign bodies or induced by drugs, Peutz-Jeghers syndrome, Addison´s disease and oral melanoma. The aim of this review is to present the main oral black lesions contributing to better approach of the patients.

Key words:Pigmentation, melanin, oral, diagnosis, management.

Metastatic malignant melanoma of palate: A review of literature and report of an unusual case

Oral malignant melanoma is a rare tumor, accounting 0.8to 1.8 % of all oral malignancies. It occurs most commonly in Japanese and Negros. Radical surgery is mainstay of the treatment. Prognosis is very poor with 5 years survival rate. We present a case of malignant melanoma in a 55 years female, metastatizing to liver spleen and vertebrae.

Mucosal malignant melanomas in head and neck surgery: a retrospective study of six patients and review of the literature

INTRODUCTION

Of all malignant processes of the oral mucosa, 0.5% are malignant melanomas. Because of late diagnosis, pattern of growth, close proximity to the bone (particularly in palatinal localizations), and the correlated infiltration, malignant melanomas have a bad prognosis.

PATIENTS AND METHODS

In this retrospective study, six cases of patients with oral mucosal malignant melanoma are evaluated, and a critical review of the literature is presented. The female to male proportion was 1:1 with an average age of 60.2 years; all patients were treated between January 1999 and July 2007. A neck dissection was performed on two patients because of clinically positive lymph nodes; one patient received interleukin 2 therapy, and three patients received postoperative radiotherapy. Two male patients died.

CONCLUSIONS

We recommend biopsy on every growing lesion, pigmented or nonpigmented, for the required diagnosis and, in cases of malignant melanoma, wide excision as a second step. Neck dissections should be performed in patients with clinically positive lymph nodes. Concerning interleukin 2 therapy, further studies should be performed in order to evaluate a routine application.

Mucosal melanomas: a case-based review of the literature

Mucosal melanoma is a rare cancer that is clearly distinct from its cutaneous counterpart in biology, clinical course, and prognosis. Recent studies have shown important differences in the frequencies of various genetic alterations in different subtypes of melanoma. Activating mutations in the c-KIT gene are detected in a significant number of patients with mucosal melanoma. This observation has resulted in the initiation of several clinical trials aimed at exploring the role of receptor tyrosine kinases that inhibit c-KIT in this patient population. We herein present a comprehensive literature review of mucosal melanoma along with case vignettes of a number of pertinent cases. We further discuss melanomas of the head and neck, the female genital tract, and the anorectum, which are the three most common sites of mucosal melanoma, with a particular focus on the diagnostic, prognostic, and therapeutic data available in the literature.

Development of an allogeneic whole-cell tumor vaccine expressing xenogeneic gp100 and its implementation in a phase II clinical trial in canine patients with malignant melanoma

A xenogeneic melanoma-antigen-enhanced allogeneic tumor cell vaccine (ATCV) is an appealing strategy for anti-cancer immunotherapy due to its relative ease of production, and the theoretical possibility that presentation of a multiplex of antigens along with a xenogeneic antigen would result in cross-reaction between the xenogeneic homologs and self-molecules, breaking tolerance and ultimately resulting in a clinically relevant immune response. In this study, we evaluated the efficacy of such a strategy using a xenogeneic melanoma differentiation antigen, human glycoprotein 100 (hgp100) in the context of a phase II clinical trial utilizing spontaneously arising melanoma in pet dogs. Our results demonstrate that the approach was well tolerated and resulted in an overall response rate (complete and partial response) of 17% and a tumor control rate (complete and partial response and stable disease of >6 weeks duration) of 35%. Dogs that had evidence of tumor control had significantly longer survival times than dogs that did not experience control. Delayed type hypersensitivity (DTH) to 17CM98 canine melanoma cells used in the whole cell vaccine was enhanced by ATCV and correlated with clinical response. In vitro cytotoxicity was enhanced by ATCV, but did not correlate with clinical response. Additionally, anti-hgp100 antibodies were elicited in response to ATCV in the majority of patients tested; however, this also did not correlate with clinical response. This approach, along with further elucidation of the mechanisms of tumor protection after xenogeneic immunization, may allow the development of more rational vaccines. This trial also further demonstrates the utility of spontaneous tumors in companion animals as a valid translational model for the evaluation of novel vaccine therapies.

Oral mucosal melanoma: a series of case reports

INTRODUCTION

Due to the rarity of oral malignant melanomas case reports are a necessary source of information. Ten new cases are reported with a minimum follow-up of 3 years.

PATIENTS AND METHODS

Patients were treated during a period of 10 years. Clinical, demographic and pathologic findings were examined.

RESULTS

In 6 males (60%) and 4 females with a mean age of 64.3 years the tumour locations were: hard palate-maxillary gingiva (3 cases), maxillary gingiva (2), lower gingiva (2), tongue (2), hard/soft palate-buccal mucosa (1). Pre-existing melanotic pigmentation had been present in 4 patients. Four patients were in stage I, 5 in stage II, and 1 in stage III. Surgical excision was the primary treatment in 9 cases. Five patients underwent simultaneous neck dissections. All patients received radiation and multimode adjuvant therapies. After a 3-year follow-up 3 patients are still alive (50% (2/4) of those presenting in stage I and 20% (1/5) in stage II).

CONCLUSIONS

Due to the rarity of oral melanoma, individual experience is limited. The poor prognosis and the different treatments reflect this situation.

Primary gingival malignant melanoma. Report of 3 cases

BACKGROUND

Malignant melanoma is rare in the oral cavity and accounts for less than 1% of all melanomas. Nevertheless, the disease can be fatal, and early diagnosis and treatment may improve prognosis dramatically. The purpose of this paper is to report 3 new cases of primary malignant melanoma of the oral cavity arising in the gingiva, and to review the literature regarding intraoral melanoma.

METHODS

Three cases are presented. One case was in the right mandibular molar area; the second in the right maxillary canine-premolar area; and the third in the left mandibular canine-premolar region. All patients were treated surgically, with postoperative radiotherapy.

RESULTS

The first patient lived for 2 years and the second for 3 years before distant metastases were diagnosed from which they subsequently died. The third patient was lost from follow-up after 18 months.

CONCLUSION

Primary oral malignant melanoma is a deadly disease. Early suspicion of this disease will allow prompt treatment and increase the prognosis for these patients.