Primary oral melanoma: Population-based incidence

Primary oral and sinonasal mucosal melanomas in Latin America: a systematic review

Primary oral and sinonasal mucosal melanomas (POSNMMs) are aggressive neoplasms with limited therapeutic alternatives. The aim of this review was to characterize the demographic, clinical, immunohistochemical, and molecular information regarding these tumors in the Latin American population. Articles published in English, Spanish, or Portuguese (1990-2022) retrieved from the PubMed/MEDLINE, Scopus, CAS, Web of Science, EBSCO, and Google Academic databases were included. Thirty-three studies, with a total of 1212 cases, were identified. Clinicopathological data were available for 870 cases and immunohistochemical and/or molecular information for 342. Nineteen studies (57.6%) reported cases of oral melanoma, three (9.1%) sinonasal melanoma, and 11 (33.3%) oral and sinonasal melanoma. Fifteen studies (45.5%) provided only clinicopathological data, 12 (36.4%) reported only immunohistochemical data, two (6.1%) shared clinicopathological and immunohistochemical data, one (3.0%) offered clinicopathological, immunohistochemical, and molecular data, one (3.0%) provided immunohistochemical and molecular data, one (3.0%) clinicopathological and molecular data, and one (3.0%) only molecular data. The mean age of individuals with POSNMMs was 58 years, and slightly more were male (male 51.3%, female 48.7%). In Latin America, POSNMMs are a rare but aggressive malignancy with a poor prognosis and limited treatment options. Although molecular data and targeted therapy are still being researched, data from Latin America indicate the need for multicenter collaborative clinical trials to unite individual and isolated efforts.

A primary oral mucosal melanoma of the hard palate with no recurrence: Report of a 10 years follow-up

BACKGROUND

Primary oral mucosal melanoma (OMM) represents an extremely rare and aggressive tumor that arises from malignant transformation and clonal expansion of melanocytes in the oral cavity. The prognosis of patients affected by OMM is quite unfavorable, with survival rates lower than those described for patients with cutaneous melanoma.

CASE REPORT

Here, we report a case of OMM in a 59-year-old Caucasian woman, who was referred for evaluation of a large asymptomatic pigmented lesion on the left side of the hard palate under the removable total denture. Incisional biopsy was performed, and histopathological analysis revealed the proliferation of spindle-shaped and pigmented epithelioid cells, with cellular pleomorphism. These cells were positive for Melan A, S-100, HMB-45, SOX-10, and Ki-67 confirming the diagnosis of OMM. The patient underwent partial maxillectomy and adjuvant radiotherapy. After treatment, she was rehabilitated with a palatal obturator prosthesis and has been in follow-up for 10 years with no evidence of disease. Due to the rarity in the oral cavity and the nonspecific signs and symptoms, the diagnosis of OMM is difficult and often overlooked.

CONCLUSION

Therefore, multidisciplinary management from diagnosis, treatment, and rehabilitation is important to increase the expectation of cure.

Oral mucosal melanoma - A systematic review

Oral mucosal melanoma (OMM) is the subject of few studies, resulting in a lack of understanding. The aim of this study is to review the current literature on OMM. The term searched was "oral mucosal melanoma" between 01/01/2000 and 03/15/2021 in the PubMed Database (MEDLINE). Patients presenting with OMM and treated in our center between January 2009 and January 2020 were included in a case series. Demographics, location, risk factors, genetic mutations, treatment performed, and overall survival (OS) rates were evaluated. The PubMed database search yielded a total of 513 results, thirty-eight articles were finally included, which amounted to 2230 cases of OMM. 13 patients were included in the case series. A male-to-female ratio of 1.28:1.00 was found with a mean age at first diagnosis of 58.2 years old. Hard palate (1060 cases) and then gingiva (794 cases) were the two main locations. No risk factors could be identified. OMM were staged III or IV at diagnosis. Mutations were described as such: KIT in 14.6% of cases, BRAF in 7%, and NRAS in 5.6%. Treatment protocols varied but radical surgery was the cornerstone treatment associated with adjuvant therapies. Immunotherapy has not been evaluated for OMM. OS rates were 43.4% at 3 years, 33.1% at 5 year and 15.4% at 10 years. OMM show distinct features from cutaneous melanoma (CM): typical locations, no identified risk factors, different mutations profile, worse prognosis with advanced stage at diagnosis. Targeted therapies are still underused compared to CM.

Primary Oral Mucosal Melanoma: A Case Series

Mucosal melanoma is an exceedingly rare and aggressive neoplasm with high mortality rate. In contrast to the cutaneous melanomas, the risk factors and pathogenesis are poorly understood. It is predominantly localized in the region of the hard palate and maxillary alveolus. Surgery is the mainstay of treatment, but it may turn out to be challenging depending on the anatomic location, extent and size of the tumor and presence of metastasis. Presented here is a series of two cases of maxillary mucosal melanoma with varied presentation.

Base of tongue metastasis of cutaneous malignant melanoma with rhabdoid and neuroendocrine features: Report of a rare case and review of the literature

Metastatic malignant melanoma (MM) represents a highly aggressive cancer associated with overall poor prognosis. Various anatomic sites can be affected, including the oral cavity and the oropharynx. It may mimic other entities by assuming a variety of clinical appearances and exhibiting a plethora of microscopic variations. Herein, we present a case of a 63-year-old male with a MM metastasizing to the base of tongue, which developed 5 years after the original diagnosis and treatment of cutaneous MM of the chest and heralded its relapse; subsequently, neurological symptoms developed as a result of metastasis to the brain. Diagnostic challenges were encountered, as the tongue lesion clinically masqueraded as a pedunculated reactive lesion and microscopically displayed unusual rhabdoid and neuroendocrine features. Tumor cells expressed S-100, HMB-45, Melan-A, and SOX-10, while most cells with rhabdoid morphology were also positive for myogenin and Myo-D1. Chromogranin and synaptophysin positivity was further noticed in a subset of cells, suggestive of focal neuroendocrine differentiation. Molecular investigation revealed mutations for the BRAF V600E gene. Divergent differentiation of tumor cells may cause diagnostic pitfalls necessitating thorough immunohistochemical analysis. The presence of rhabdoid features and neuroendocrine differentiation are very uncommon, while their co-existence is extremely rare. Better characterization of such microscopic variations in MMs with evaluation of their potential biologic significance is warranted.

Actionable Mutation Profile of Sun-Protected Melanomas in South America

ABSTRACT

Melanomas that arise in sun-protected sites, including acral and oral mucosal melanomas, are likely under the control of unique, specific mechanisms that lead to mutagenesis through various pathways. In this study, we examined somatic mutations in tumors by targeted sequencing using a custom Ion Ampliseq Panel, comprising hotspots of 14 genes that are frequently mutated in solid tumors. Tumor DNA was extracted from 9 formalin fixation, paraffin-embedded sun-protected melanomas (4 primary oral mucosal melanomas and 5 acral lentiginous melanomas), and we identified mutations in the NRAS, PIK3CA, EGFR, HRAS, ERBB2, and ROS1 genes. This study reveals new actionable mutations that are potential targets in the treatment of photo-protected melanomas. Additional studies on more of these melanoma subtypes could confirm our findings and identify new mutations.

The 'AEIOU' system to identify primary oral melanoma

Primary oral melanoma (POM) is a rare entity that is often asymptomatic and is associated with a poor prognosis. Following the example of the ABCDE acronym for the clinical diagnosis of early cutaneous melanoma, we would like to introduce another acronym, AEIOU, to identify lesions that are clinically suspicious for POM. The letter "A" means age older than 50; "E" means ethnicity in reference to the higher occurrence among Asians, Hispanics, and Africans; "I" means irregularity in reference to irregular borders or color; "O" means oral palate, the most frequent site of POM; and "U" means ulceration. To the best of our knowledge, this paper is the first to describe an acronym AEIOU as a diagnostic aid for POM among health practitioners and the general population. Future studies should test the acronym's sensitivity and specificity for POM diagnosis in clinical practice.

A Large Oral Melanoma: A Case Report of a Rare but Aggressive Malignancy

A variety of black-pigmented lesions of the oral cavity can be found, ranging from harmless benign lesions such as melanotic macule, smoker's melanosis, amalgam/graphite tattoos, and pigmented nevus to a life-threatening oral malignant melanoma. Oral melanoma is a rare and aggressive malignant tumor that originates from melanocytes' proliferation and accounts for only 0.5% of all oral malignancies. The etiology is unknown. Most oral melanomas are present at the palate and the upper alveolar ridge, whereas occurrences at the buccal mucosa, the lower alveolar ridge, and the lip are rare, with only a few reports in the literature. The diagnosis is confirmed by a biopsy. The prognosis is poor, with a 5-year survival rate of ~20%. In this report, we present a case of large oral melanoma at the right buccal mucosa involving the right lower alveolar ridge and lip commissure, which are relatively unusual locations for oral melanoma. In addition, immunohistochemical markers used for diagnostic, therapeutic, and prognostic decision-making of oral melanoma are also discussed.

Pigmented Lesions

Oral pigmented lesions have a wide range of clinical presentations, some of which correlate with cutaneous pigmented lesions. This article highlights these correlates and underscores important differences that can potentially have clinical impact. Moreover, given a nonspecific presentation of an oral pigmented lesion, the article provides a reference to aid clinicians with differential diagnoses based on clinical features. This article is an overview of pigmented lesions of the oral cavity, including localized reactive pigmented lesions, neoplastic pigmented lesions, and pigmented lesions as sequelae of a systemic disease.

Prevalence of malignant melanoma in anatomical sites of the oral cavity: A meta-analysis

Oral malignant melanoma (OMM) is a very rare disease entity accounting <1% of all other melanomas. Till date, no comprehensive meta-analysis has been conducted regarding the prevalence of malignant melanoma in the oral cavity. Therefore, the present meta-analysis was conducted to update on the prevalence of malignant melanoma in anatomical sites of the oral cavity. Literature search was performed to congregate reports of last 10 years using databases, such as PubMed and ScienceDirect. The search strings used were "palate," "buccal," "gingiva," "gum," "maxillary," "mandibular," "lip," "tongue," "melanoma," "oral melanoma," "malignant melanoma," "prognosis," "risk factors," "noncutaneous" and "diagnosis" of OMM by combining terms using the Boolean operators. MedCalc 16.4.3 software was used for the analysis. "Random effects model" was used in the analysis due to significant heterogeneity in the studies. Proportion method was used to analyze the prevalence. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed to report the analysis. Out of 130 studies screened, 19 were included in the meta-analysis and a total of 1323 patients were included. The median age of the patients was found to be 61.87 ± 7.78 years (confidence interval 53.8-67 years). All the screened studies showed significant heterogeneity in gender as well as tumor sites (P < 0.0001). Palate (34.29%) was the most commonly affected site in OMM patients. Overall, the results of the meta-analysis suggest that palate is the most prevalent site in OMM. Furthermore, OMM is high in patients between the fifth and sixth decade of life with a male predominance.

Black and Brown Oro-facial Mucocutaneous Neoplasms

Black and brown-colored mucocutaneous lesions present a differential diagnostic challenge, with malignant melanoma being the primary clinical concern. The vast majority of pigmented lesions in the head and neck region are the result of benign, reactive factors such as post-inflammatory melanosis. However, it is not uncommon to discover a range of muco-cutaneous black and brown neoplasms in the oro-facial area. The majority of black/brown pigmented neoplasms are melanocytic in origin; these are neoplasms of neural crest derivation. Melanocytic nevi are a diverse group of benign neoplasms that are the result of specific oncogenic mutations. They are common on cutaneous surfaces but can manifest in mucosal sites. Currently, nevi are classified based on clinical and histological criteria. The most common cutaneous and oral mucosal nevus is the acquired melanocytic nevus; nevi do not pose an increased risk for the development of malignant melanoma. Emerging information on specific genetic differences supports the notion of biologically distinct nevi. This article will review the classic clinical and microscopic features of nevi commonly found in the head and neck region, and discuss emerging concepts in nevus pathogenesis and taxonomy. Melanoma is a malignant melanocytic neoplasm and is a result of cumulative genetic deregulation. The etiology of malignant melanoma (MM) is multifactorial and includes underlying genetic susceptibility, UV radiation, skin-type, and race. The majority of MM occurs on cutaneous surfaces and less commonly on mucosal and extra-cutaneous visceral organs. Regardless of location, MM exhibits clinical-pathological features that relate to horizontal or vertical tumor spread. Cutaneous and mucosal MM typically present as asymmetrical, irregularly bordered, large (> 0.5 cm), heterogeneous brown-black lesions with foci of erythema, atrophy or ulceration. As with melanocytic nevi, advances in melanomagenesis research have revealed primary oncogenic BRAF and NRAS mutations associated with cutaneous MM. Unlike their cutaneous counterparts, mucosal melanomas exhibit primary oncogenic alterations in c-KIT and other genes. This article will discuss the role of specific primary oncogenic and secondary/tertiary genetic defects in differential clinical presentation, anatomic distribution, future classification changes, and targeted therapy of melanoma. The clinical and microscopic features of mucosal melanomas and a summary of management guidelines will be discussed. Additionally, this article will cover the salient features of melanocytic neuroectodermal tumor of infancy, a neoplastic entity that can involve the oro-facial region, and the clinical-pathological features of selected, commonly occurring pigmented ectodermally-derived neoplasms that are often part of the clinical differential diagnosis of black-brown pigmented lesions.

Data Set for the Reporting of Mucosal Melanomas of the Head and Neck: Explanations and Recommendations of the Guidelines From the International Collaboration on Cancer Reporting

Standardized pathologic reporting for cancers allows for improved communication for patient care and prognostic determination. If used universally, synoptic reporting enhances comparing data globally for scientific leverage. The International Collaboration on Cancer Reporting is a nonprofit organization whose mission is to develop evidence-based, universally available surgical pathology reporting data sets. Multiple different sites within the head and neck may be affected by mucosal melanoma, whose behavior and patient outcome are not equivalent to carcinomas of the corresponding sites. Factors such as Breslow thickness and Clark depth of invasion applied to cutaneous melanomas do not yield any prognostic significance in mucosal sites, and thus are not meaningful. Likewise, margin assessment is unique in head and neck sites. Further, the genetic profile of mucosal melanomas is different from that of most cutaneous tumors. Thus, within the head and neck region, mucosal melanoma is a distinct entity for which a dedicated data set was developed for implementation. The elements that comprise the core (required) and noncore (recommended) elements are discussed.

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.

Desmoplastic melanoma of the oral cavity: diagnostic pitfalls and clinical characteristics

Objectives

Desmoplastic melanoma of the oral cavity is an extremely rare condition that is often confused on initial diagnosis with non-melanotic benign lesion or spindle cell tumors. The purpose of this article was to raise awareness of the disease using a literature review.

Materials and Methods

We analyzed 19 desmoplastic melanoma cases reported in the literature and added our experience. Data on clinical, histopathology, treatment, and survival were retrieved and analyzed. Survival analysis was by the Kaplan-Meier method.

Results

Initial clinical and histopathological features were indistinctive, and a definite diagnosis of desmoplastic melanoma at initial assessment was possible in only 23.5% of cases. Among tests, immunohistochemical studies for S-100 and vimentin were all positive. The 5-year disease-free survival rate for oral desmoplastic melanoma was 0%, and the 5-year overall survival rate was 55.0%.

Conclusion

Oral desmoplastic melanoma has a high percentage of initial misdiagnosis and propensity for local recurrence. Thus, careful initial diagnosis and adequate surgery may result in improved overall survival.

Clinical investigation of 38 cases of oral mucosal melanoma: A multicentre retrospective analysis in Japan

BACKGROUND/OBJECTIVES

The aim of the present study was to investigate treatment modalities and outcomes in oral mucosal melanoma.

METHODS

The clinical and pathological data of 38 consecutive patients with oral mucosal melanoma were retrospectively analyzed. Patients' characteristics were analyzed and overall survival (OS) rates were calculated.

RESULTS

Sixteen patients had stage III (42%), 19 IVA (50%), and three had stage IVC (8%) disease. Among the therapeutic approaches used, 31 patients (82%) received radical therapy (surgery +/- chemotherapy). The 5-year OS rate was 40%. Five-year OS rates according to the clinical stage were 71% for stage III, 24% for stage IVA, and 0% for stage IVC. Five-year OS rates according to therapeutic approaches were 52% in the radical therapy group and 0% in the palliative therapy and best supportive care groups.

CONCLUSIONS

The results of this multicentre retrospective analysis of patients with oral mucosal melanoma suggest that radical therapy based on surgical treatments with complete surgical excision with clear margins leads to a better prognosis.

Update from the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Mucosal Melanomas

The updated edition of The World Health Organization Classification of Tumours of the Head and Neck includes discussions on mucosal melanoma of both the sinonasal and oral cavity. Since the prior edition, sinonasal origin is now recognized as the most common site of occurrence of mucosal melanoma in the head and neck (66%) with oral cavity representing 25% of cases. Histologic features of mucosal melanomas vary widely from spindled, epithelioid, and pleomorphic to rhabdoid, plasmacytoid and undifferentiated. Additionally, mucosal melanomas are commonly amelanotic (or minimal pigmentation) (~50%) leading to overlapping features and diagnostic challenges in differentiating mucosal melanomas from other small cell/undifferentiated sinonasal tumors. Since the last edition, formal staging of head and neck mucosal melanomas was added to the American Joint Committee on Cancer entities, though the traditional histologic features that have prognostic significance in cutaneous melanomas fail to stratify mucosal melanomas (i.e. tumor thickness, ulceration). Interestingly, while melanomas of all sites are a malignancy derived from melanocytes, mucosal melanomas are now recognized to have distinct molecular alterations compared to cutaneous or uveal melanomas. BRAF V600E mutations are rare (<6%) in mucosally derived melanomas compared to a rate of 50% in cutaneous melanomas. CD117 (C-Kit) mutations are the most common alteration encountered (~25%) in mucosal sites with potential therapeutic targetability. The recognition of the distinct genetic changes in this subgroup of melanomas means that therapy advances in cutaneous melanomas may not translate to head and neck mucosal melanomas and clinical trials specific to this subgroup of patients are needed.

Melanoma of the Oral Cavity: an Analysis of 46 New Cases with Emphasis on Clinical and Histopathologic Characteristics

Melanoma of the oral cavity is a rare malignancy that carries a poor prognosis. We identified 46 new cases of both primary and metastatic melanoma to the oral cavity. Following IRB approval, these cases were obtained from the Oral Pathology Biopsy Service archives of the UF College of Dentistry (1994-2014), the UK College of Dentistry (1997-2015), and the UM Medical Center (1988-2015). All slides were reviewed. The location, age, race, gender, clinical impression, duration of lesion, histopathologic diagnosis, and histopathologic features were recorded. Cases from the facial skin and those with an ambiguous diagnosis were excluded. Forty-six cases fulfilled the inclusion criteria with 32 primary cases, 11 known metastases, and 3 cases where metastasis could not be excluded. The primary cases included a total of 20 females and 12 males with an average age of 66.7 (range 27-95), and the majority (80 %) of the patients were Caucasian when race was known. Twenty-two of the 32 primary cases (68.8 %) were located in the maxillary mucosa, 5 in the mandibular mucosa or bone, and 5 in other locations. The clinicians' impressions varied from benign fibrous growths to high grade malignancies. The histopathology varied widely among the cases, however two cell types predominated (often in combination): epithelioid cells (50.0 %) and spindle cells (50.0 %). Only 53.1 % demonstrated melanin pigmentation. Oral melanoma remains one of the most diverse clinical and histopathologic diagnoses. Better understanding of this neoplasm may promote earlier diagnosis and may lead to improved outcomes.

In vivo reflectance confocal microscopy for evaluating melanoma of the lip and its differential diagnoses

OBJECTIVE

To improve prebiopsy diagnostic accuracy and surgical management of pigmented appearing lesions on the lips, particularly melanoma, using in vivo reflectance confocal microscopy (RCM).

STUDY DESIGN

Prospective case series over a 12-month period between 2015 and 2016. The setting was two specialist dermatology referral centers with expertise in confocal microscopy. The study population was a consecutive sample of patients with pigmentation of the lip for which the cause was uncertain clinically, whose differential diagnosis included melanoma, and who had undergone both in vivo RCM and subsequent biopsy. The outcome measures were RCM features, dermoscopy features, and histopathological diagnosis. Results were reported by descriptive analysis and correlations made between RCM features and histopathology.

RESULTS

Eight patients were recruited for the study. In vivo RCM facilitated the targeting of small biopsies to identify two in situ oral melanoma recurrences and successfully mapped an in situ oral melanoma before wide excision. Suprabasal dendritic pagetoid cells and epidermal disarray on RCM were useful indicators for in situ melanoma of the lip. Previously described dermoscopy features for mucosal melanoma were not very helpful in diagnosing melanoma in our series. Challenges included evaluating inflamed lesions with pigment incontinence.

CONCLUSIONS

RCM can assist in the diagnosis and management of pigmented lip lesions, but additional studies are required to further evaluate these initial observations.

Primary Gingival Melanoma: An Important Entity

Primary melanoma of the mandibular gingiva is extremely rare. It is often misinterpreted as a benign pigmented process. The prognosis of this entity is very poor. We report here the first case of primary gingival melanoma described in the Tunisian literature about a 55-year-old smoker having cerebral and pulmonary metastases from gingival melanoma at diagnosis. Our patient underwent brain radiotherapy at a dose of 18 Gy in three sessions but he died with a decline of 3 months before starting systemic therapy. Therefore, each new case should be illustrated to make clinicians aware about the importance of the early diagnosis to improve the poor diagnosis of this entity.

Survival Outcomes of Mucosal Melanoma in the Head and Neck: Case Series and Review of Current Treatment Guidelines

PURPOSE

Malignant mucosal melanoma of the head and neck (MMHN) is an aggressive and rare neoplasm with poor long-term outcomes. The aim of this study is to evaluate the outcomes of patients treated by a single-institution head and neck multidisciplinary team.

MATERIALS AND METHODS

In this retrospective case series, all MMHN cases treated at the Royal Melbourne Hospital from 1990-2015 were retrospectively reviewed. Patient demographic characteristics (eg, age), treatment offered, pathology, and outcomes were collected, tabulated, and correlated with outcomes. Survival outcomes were calculated by the Kaplan-Meier method. Comparison was made between oral and sinonasal melanomas.

RESULTS

A total of 16 cases were identified. Two were excluded because of inaccessible data. Of the 14 remaining cases, 8 were sinonasal melanomas and 6 were oral cavity melanomas. Sinonasal tumor patients presented with epistaxis or visual impairment. Oral melanoma patients presented with pigmented lesions or ulceration. Follow-up ranged from 4 months to 11 years. In 2 patients, locoregional recurrences developed that were successfully re-excised. Six patients died of distant metastases despite clear surgical margins. Two patients with sinonasal melanomas died of extensive local disease with intracranial invasion. One patient died 4 years after diagnosis without disease. There were no failures in the neck. The 2- and 5-year overall survival rates were 63.3% and 31.7%, respectively, by the Kaplan-Meier method. The difference in survival between oral and sinonasal melanomas was not statistically significant.

CONCLUSIONS

Despite clear surgical margins, MMHN has a poor prognosis and most deaths are due to distant metastases. Systemic therapies such as those used in cutaneous melanoma treatment might be used in the future for MMHN.

Primary mucosal melanoma of the oral cavity: current therapy and future directions

BACKGROUND

Primary mucosal melanoma of the oral cavity is a highly aggressive malignancy of melanocytic origin. The aim of this study is to report a case series of oral mucosal melanomas (OMMs) and provide a review of the literature with regard to treatment guidelines for and prognosis of this pathologic entity.

STUDY DESIGN

We report three cases of OMMs treated in our institutions and the results of a literature review, in which the words "oral" and "mucosal melanoma" were used as the main keywords.

RESULTS

Surgical resection of the primary tumor with wide resection margins appears to be the recommended primary treatment modality with the aim to achieve tumor-free margins. Elective neck dissection and adjuvant radiotherapy have been advocated for locoregional control. Chemotherapy has not been shown to improve survival and is mainly used for palliative purposes. Immunotherapy and biochemotherapy seem to significantly improve survival and could open new therapeutic horizons.

CONCLUSIONS

The prognosis of OMMs remains poor despite treatment. Early diagnosis and aggressive surgical resection followed by adjuvant therapies could be the key to improving survival. Multicenter randomized clinical trials, which may be difficult to conduct because of the rarity to the lesion, would aid in the development of new strategies.

Oral malignant melanoma: Report of three cases with literature review

Primary oral melanoma is known to be an extremely rare and aggressive neoplasm arising from the mucosal epithelium of the oral cavity especially upper jaw (palate or alveolar gingivae). Malignant melanoma that does not originate in the skin is a very rare disease and is considered one of the most deadly of all human neoplasms. Oral malignant melanoma (OMM) represents about 1% of all melanomas and approximately 0.5% of all oral malignancies. OMM has been reported in patients aged 20 to 80 years and has a male predilection. Because most mucosal melanotic lesions are painless in their early stages, so delayed recognition and subsequent treatment result in worst prognosis. Here, we report three cases with significant heterogeneity in morphological features and biologic behavior.

Update on primary head and neck mucosal melanoma

Primary mucosal melanomas (PMMs) of the head and neck are uncommon malignancies that arise mainly in the nasal cavity and paranasal sinuses, followed by the oral cavity. The mainstay of treatment is radical surgical resection followed by adjuvant radiotherapy in selected patients with high-risk features. Multimodality therapy has not been well studied and is not standardized. Adjuvant radiotherapy seems to improve locoregional control but does not improve overall survival (OS). Elective neck dissection is advocated in patients with oral PMM. Systemic therapy should be considered only for patients with metastatic or unresectable locoregional disease. Despite improvements in the field of surgery, radiotherapy, and systemic therapy, patients with PMM still face a very unfavorable prognosis (5-year disease-free survival [DFS] <20%) with high rates of locoregional recurrence and distant metastasis. The present review aims to summarize the current state of knowledge on the molecular biology, pathological diagnosis, and management of this disease.

Primary Malignant Melanoma of the Lip: A Report of 48 Cases

PURPOSE

Lip melanoma (LM) is a rare malignant tumor and well-established treatment protocols for it are in short supply. The objective of this study was to evaluate the outcome of treatment modalities and explore the prognostic factors.

PATIENTS AND METHODS

A retrospective chart review was performed on 48 patients with primary LM treated in the authors' hospital from January 1992 to November 2013. The clinical characteristics and treatment modalities were identified and correlated with the outcomes.

RESULTS

The 5-year overall survival (OS) rate was 56.1%, and the rate of cervical lymph node (CLN) metastasis was 46% (22 of 48). A tumor of at least 4 cm (P = .001), nodular types (P = .003), and CLN (P < .0001) were independent prognostic factors for OS. Twenty-five patients died during follow-up, mainly from to neck recurrence (14 of 25). Chemotherapy significantly improved the 5-year OS rate in patients with stage IV LM (P = .03), but not in those with stage III (P = .8).

CONCLUSIONS

LM has a lower CLN and distant metastasis rate and a better prognosis than other oral mucosal melanomas. A long history of melanin pigmentation is a dangerous sign for all patients, and smoking seems to be associated with LM in male patients. Tumor size (≥4 cm), nodular type, and CLN positivity are poor prognostic factors. A wide excision with close observation is advocated as the primary treatment for stage III LM. Adjuvant chemotherapy is useful for patients with stage IV cancer, but not for those with stage III.

Melanoma of the oral cavity: pathogenesis, dermoscopy, clinical features, staging and management

Primary mucosal melanoma of the oral cavity is an exceedingly rare neoplasm which is estimated to comprise 1-2% of all oral malignancies. In contrast to cutaneous melanomas, the risk factors and pathogenesis are poorly understood. The predominate localization of primary oral melanoma is hard palate and maxillary alveolus. Dermoscopy may be utilized as an adjunctive tool in the clinical differential diagnosis of oral mucosal melanoma whenever the lesion is accessible with a dermoscope. Surgery is the mainstay of treatment, but it may be challenging depending on the location of the tumor within the oral cavity and its size. Adjuvant therapy with dacarbazine, platinum analogs, nitrosoureas and interleukin-2 have been utilized with low response rates. Imatinib may be effective for patients with with c-Kit gene mutations. Sunitinib and dasatinib have been reported effective in selected cases. Vemurafenib and dabrafenib are targeted agents for patients with BRAF mutation-positive melanoma. Ipilimumab, an anti-cytotoxic T-lymphocyte antigen 4 antibody and pembrolizumab, a monoclonal antibody targeting programmed death 1 receptor may be a feasible treatment option in patients with metastatic mucosal melanoma.

Heparanase expression correlates with poor survival in oral mucosal melanoma

Oral mucosal melanoma (OMM) is a lethal cancer with a poor prognosis. Despite the great interest in heparanase (HPSE) as a potential anticancer therapy target, the prognostic role of HPSE in oral mucosal melanoma has not been elucidated. In this study, we investigated HPSE expression in OMM tissues and examined its association with clinical outcome. A total of 81 patients with OMM were enrolled in this study. We examined the expression of HPSE in OMM, and its staining extent, intensity and cellular localization were analyzed for clinical significance. HPSE staining was positive in 81 % of tumors (66 of 81 patients) and was negative in the remaining 19 % (15 patients). The median survival time and the 5-year survival rate were 12 months and 7.0 % in the high-heparanase group, 35 months and 36.4 % in the low-heparanase group and 62 months and 53.3 % in the none-heparanase group (P = 0.001). In univariate survival analysis of oral mucosal melanoma, AJCC Stage, heparanase level, heparanase location and tumor size were the clinical parameters related to overall survival. In Cox analysis, overall survival time was significantly dependent on AJCC stage and heparanase level, but not tumor size and heparanase location. Heparanase is frequently expressed in oral mucosal melanoma, and its expression levels inversely correlate with the survival rates of OMM patients, clearly indicating that heparanase is a reliable prognostic factor for this malignancy and an attractive target for anticancer drug development.

Primary oral melanoma: a histopathological and immunohistochemical study of 22 cases of Latin America

OBJECTIVE

The aim of this study was to analyze the histopathological and immunohistochemical characteristics of 22 cases of primary oral melanomas (OM).

STUDY DESIGN

Twenty two cases of primary oral melanoma were analyzed by description of their histopathological features and immunohistochemical study using the antibodies S-100, HMB-45, Melan-A and Ki-67.

RESULTS

The mean age was 58 years and 14 cases were female. The main affected sites were the hard palate, followed by the upper gingiva. Microscopically, 15 cases presented level III of invasion, 2 cases were amelanotic and 13 showed a mixed epithelioid and plasmacytoid or spindle cells composition. Some cases showed necrosis, perivascular and perineural invasion. S-100 and HMB-45 were positive in all cases, but 3 cases were negative for Melan-A. The proliferative index with Ki-67 was high, with labeling index ranging from 15.51% to 63% of positive cells.

CONCLUSION

S-100 and HMB-45 are more frequently expressed than Melan-A in primary oral melanomas and these markers are helpful to confirm the diagnosis.

Oral melanotic macule and primary oral malignant melanoma: epidemiology, location involved, and clinical implications

BACKGROUND

Oral malignant melanoma must be differentiated from melanotic macule.

STUDY DESIGN

Retrospective review of 2 series of oral melanotic macule (n = 52) and oral melanoma (n = 130) were conducted to investigate the epidemiology and location involved and assess their differences.

RESULTS

The mean age of oral melanotic macule patients was 47.3 years, with female:male ratio 2.1 and the lower lip being the predominant location. The mean age of oral melanoma patients was 53.8 years, with no observed sex predilection and the main locations being palate and gingiva. Differences between the 2 cohorts in age (P = .006), gender (P = .014), and lesion site (P < .001) were noted. In this review, 1 case of oral melanotic macule was found to subsequently develop into melanoma.

CONCLUSIONS

Oral melanotic macule may possess malignant potential. Biopsy is recommended to differentiate oral melanoma from melanotic macule for male patients >60 years old with suspected melanotic macule lesion located on the palate.

Primary oral mucosal melanoma: advocate a wait-and-see policy in the clinically N0 patient

PURPOSE

Oral mucosal melanoma (OMM) is a rare disease associated with a very poor prognosis. Because well-established treatment protocols for OMM are in short supply, prognostic information regarding recent treatment modalities for this disease were sought.

PATIENTS AND METHODS

A retrospective chart review was performed of 61 patients who were treated for OMM from 1998 through 2005. The clinical features and treatment modalities were identified and correlated with the outcomes.

RESULTS

There were 41 male and 20 female patients (ratio, 2.1:1) with a mean age of 54.1 years. The mean follow-up was 31.9 months, and the overall 2-year and 5-year survival rates were 51.1% and 30.3%, respectively. According to the seventh edition of the American Joint Committee on Cancer staging system, there were 31 patients (50.8%) with stage III tumors. A more advanced stage and a tumor of at least 2 cm were associated with worse survival (P < .001 and P = .036, respectively). Elective lymph node dissection and biochemotherapy were not associated with a higher total survival rate (P = .53 and P = .76, respectively).

CONCLUSIONS

OMM has a male predilection. The seventh edition of the American Joint Committee on Cancer stage and tumor size are effective prognostic parameters for patients with OMM. The American Joint Committee on Cancer staging system provides useful information for predicting the ultimate outcome and should be used as the primary staging system. Elective node dissection and adjuvant biochemotherapy offer no additional advantage in increasing the patient survival rate. A wait-and-see policy is advocated for patients with clinical stage N0 cancer.

Neck dissection and post-operative chemotherapy with dimethyl triazeno imidazole carboxamide and cisplatin protocol are useful for oral mucosal melanoma

Background

Oral mucosal melanoma (OMM) is a clinically rare disease with poor prognosis. Various treatment methods have been investigated with the aim of improving the prognosis. This study aimed to analyze the data of a single institution in the management of OMM.

Methods

A total of 78 consecutive OMM patients were included in this retrospective study. The intraoral lesion was treated either by cryotherapy, surgery or both; the neck was treated by neck dissection or observation; post-operative chemotherapy with dimethyl triazeno imidazole carboxamide and cisplatin was performed in some patients. The Kaplan-Meier method was used for statistical analysis.

Results

Among the 78 patients, there were 50 males and 28 females with an average age of 53.8 years (ranging from 27 to 85 years). The most common sites of OMM were the hard palate and gingiva. The main cause of death in OMM was distant metastasis. No significant difference was found between the intraoral/cervical lesion recurrence/post-operative distant metastasis and the intraoral lesion site/biopsy method/treatment method. The metastasis rate of cervical lymph node was high in the OMM patients, even in the patients with clinically negative necks. Cervical lesion recurrence was correlated with N stage and intraoral lesion recurrence. The survival period was longer in the patients with T3 staging, clinical stage III disease, with post-operative chemotherapy and without post-operative distant metastasis when compared to those patients with T4a staging, clinical stage IV disease, without post-operative chemotherapy and with post-operative distant metastasis.

Conclusions

Radical surgery including wide intraoral resection and neck dissection is recommended for OMM patients. Post-operative chemotherapy may also be beneficial for both primary and recurrent OMM patients.

Oral malignant melanomas and other head and neck neoplasms in Danish dogs--data from the Danish Veterinary Cancer Registry

Background

Head and neck cancers (HNC) are relatively common and often very serious diseases in both dogs and humans. Neoplasms originating in the head and neck region are a heterogeneous group. HNC often has an unfavourable prognosis and the proximity of the tissue structures renders extirpation of tumours with sufficient margins almost incompatible with preservation of functionality. In humans oral malignant melanoma (OMM) is extremely rare, but represents a particular challenge since it is highly aggressive as is the canine counterpart, which thus may be of interest as a spontaneous animal model.

Methods

Canine cases entered in the Danish Veterinary Cancer Registry (DVCR) from May 15th 2005 through February 29th 2008 were included in this study. Fisher's exact test was used to compare proportions of HNC in dogs and humans as well as proportions of surgically treated cases of OMM and squamous cell carcinomas (SCC). Also the proportions of benign and malignant neoplasms of different locations in dogs were compared using Fisher's exact test.

Results

A total of 1768 cases of neoplasias (679 malignant, 826 benign, 263 unknown) were submitted. Of all neoplasias HNC accounted for 7.2% (n = 128). Of these, 64 (50%) were malignant and 44 (34%) benign. The most common types of malignant neoplasia were SCC (18; 28% of malignant), OMM (13; 20% of malignant), soft tissue sarcoma (11; 17% of malignant) and adenocarcinoma (5; 11% of malignant). The most common types of benign neoplasms were adenoma (7; 16% of benign), polyps (6; 14% of benign) and fibroma (5; 11% of benign).

Conclusions

In the current study, the proportion of neoplasia in the head and neck region in dogs in Denmark was similar to other canine studies and significantly more common than in humans with a large proportion of malignancies. Spontaneous HNC in dogs thus, may serve as a model for HNC in humans.

Canine OMM is a spontaneous cancer in an outbred, immune-competent large mammal population and could be a clinical model for OMM in humans.