Oral malignant melanoma: A review of the literature

Diagnosis and Treatment of an Unusual Maxillary Gingiva Malignant Melanoma Arising Around Dental Implant

BACKGROUND

Oral mucosal malignant melanoma (OMMM) arises from malignant melanocytes, and the most affected age, sex, and site are 20 to 83 years, male, and the mucosa of hard palate and maxillary gingiva, respectively. Despite several cases of OMMM have been published in the literature, cases of malignant melanoma arising around the dental implant are rarely reported.

CASE SUMMARY

A 59-year-old male was admitted to our Department with the complain of gingival black pigmentations following dental implant treatment for 3 years. Intraoral examination revealed a painless black lobulated mass around maxillary gingiva and alveolar fossa of dental implant (first molar). CBCT revealed bone destruction around the implant. Positron emission tomography/computed tomography confirmed the presence of tumoral lesion, which was diagnosed as right maxillary gingiva malignant melanoma (T4aN0M0). Partial maxillectomy+buccal fat pad transfer+free tissue patch repair were carried out. Pathologic analyses confirmed the diagnosis of malignant melanoma. The postoperative course was uneventfully, the patient is undergoing follow-up without any evidence of recurrence.

CONCLUSION

Our report showed that an ill-fitting dental implant may cause OMMM. Excisional biopsy with sufficient surgical margins allows complete removal and final diagnosis of OMMM. Early diagnosis and treatment are recommended.

Differential Diagnosis of Pigmented Lesions in the Oral Mucosa: A Clinical Based Overview and Narrative Review

This paper examines the clinical differentiation of pigmented lesions in the oral mucosa, which poses significant diagnostic challenges across dental and medical disciplines due to their spectrum from benign to potentially malignant conditions. Through a literature review and analysis of clinical cases, this study clarifies current diagnostic methodologies, with an emphasis on differential diagnosis, to provide a practical guide for clinicians. The classification of pigmented lesions, such as endogenous, focal melanocytic, and multifocal pigmentation, based on clinical and histological features, highlights the necessity for a structured and informed approach. A retrospective examination of cases from our oral medicine and pathology clinic, coupled with analysis of photographic and histological records, aids in classifying these lesions. This fosters a better understanding and promotes informed discussions among clinicians, ultimately aiming to enhance early and precise diagnosis, thus improving patient management and outcomes.

Primary mucosal melanomas of the head and neck are characterised by overexpression of the DNA mutating enzyme APOBEC3B

AIMS

Primary head/neck mucosal melanomas (MMs) are rare and exhibit aggressive biologic behaviour and elevated mutational loads. The molecular mechanisms responsible for high genomic instability observed in head/neck MMs remain elusive. The DNA cytosine deaminase APOBEC3B (A3B) constitutes a major endogenous source of mutation in human cancer. A3B-related mutations are identified through C-to-T/-G base substitutions in 5'-TCA/T motifs. Herein, we present immunohistochemical and genomic data supportive of a role for A3B in head/neck MMs.

METHODS AND RESULTS

A3B protein levels were assessed in oral (n = 13) and sinonasal (n = 13) melanomas, and oral melanocytic nevi (n = 13) by immunohistochemistry using a custom rabbit α-A3B mAb (5210-87-13). Heterogeneous, selective-to-diffuse, nuclear only, A3B immunopositivity was observed in 12 of 13 (92.3%) oral melanomas (H-score range = 9-72, median = 40) and 8 of 13 (62%) sinonasal melanomas (H-score range = 1-110, median = 24). Two cases negative for A3B showed prominent cytoplasmic staining consistent with A3G. A3B protein levels were significantly higher in oral and sinonasal MMs than intraoral melanocytic nevi (P < 0.0001 and P = 0.0022, respectively), which were A3B-negative (H-score range = 1-8, median = 4). A3B levels, however, did not differ significantly between oral and sinonasal tumours (P > 0.99). NGS performed in 10 sinonasal MMs revealed missense NRAS mutations in 50% of the studied cases and one each KIT and HRAS mutations. Publicly available whole-genome sequencing (WGS) data disclosed that the number of C-to-T mutations and APOBEC3 enrichment score were markedly elevated in head/neck MMs (n = 2).

CONCLUSION

The above data strongly indicate a possible role for the mutagenic enzyme A3B in head/neck melanomagenesis, but not benign melanocytic neoplasms.

Oral Pathology in Portuguese Dogs: An Eight-Year Biopsy-Based Retrospective Study

The oral cavity of the dog can be the site of several types of pathology including both benign and malignant lesions. The aim of this study was to analyze the frequency and clinical-pathological characteristics of oral lesions present in a cohort of Portuguese dogs. A retrospective observational cross-sectional study on 704 canine oral lesions submitted for histopathological diagnosis to a Veterinary Pathology Center in the north of Portugal from 2010 to 2017 was performed. Gender, age, location of the lesion and the histopathological diagnosis was analysed. From the 704 cases included, 307 (43.6%) were females and 397 (56.4%) males. The mean age was 9.53 ± 3.6 years-old (range 3 to 240 months). The site most frequently affected was the gingiva (n = 283; 40.2%). 342 (48.6%) cases were malignant neoplasms, most represented by oral melanoma (n = 129; 37.7%). 256 (36.4%) cases were benign neoplasms, most represented by fibromatous epulis of periodontal ligament origin/peripheral odontogenic fibroma (FEPLO/POF) (n = 208;81.3%). 106 (15%) were non-neoplastic lesions, most represented by gingival hyperplasia (n = 25, 23.6%). This study provides useful information about frequency and distribution of oral lesions in dogs over a period of eight years allowing valuable comparison with other countries and other species. The most common benign tumours were FEPLO/POF while oral melanoma was the most common malignant tumour.

PRAME immunohistochemistry is useful in differentiating oral melanomas from nevi and melanotic macules

BACKGROUND

Oral melanocytic neoplasms pose a diagnostic challenge to pathologists owing to their rarity relative to those in the skin. The utility of PRAME in distinguishing nevi from melanomas has been established in the skin, but limited information exists regarding its usefulness in the oral cavity.

METHODS

Thirty-five previously diagnosed pigmented oral lesions were retrospectively evaluated with PRAME. The lesions consisted of 16 oral nevi, 10 melanomas, and 10 melanotic macules.

RESULTS

Strong and diffuse nuclear PRAME staining was observed in all but one of the oral melanomas, which showed no staining. No nuclear PRAME staining was observed in any of the oral nevi or melanotic macules.

CONCLUSIONS

PRAME is a useful tool in the evaluation of oral melanocytic neoplasms. Our data indicate that PRAME is a highly specific but incompletely sensitive marker of oral melanoma. Larger studies could further illuminate the diagnostic value of PRAME in oral lesions.

Blue Nevus of the Hard Palate: The Importance of a Careful Examination in an Emergency Setting

Oral common blue nevus is an asymptomatic, benign, rare, pigmented lesion and sometimes clinically indistinguishable from other pigmented lesions such as the cellular blue nevus or early-stage malignant melanoma. Since it shows clinical similarities with a malignant lesion and with cellular blue nevus that can itself suffer malignant transformation, the decisive diagnosis is crucial for adequate treatment, follow-up, and prognosis. Diagnosis confirmation is given by histological analysis, the reason why most oral pigmented lesions are excised. The following case presents an asymptomatic oral pigmented lesion of the hard palate discovered during observation in an emergency setting due to an abscess of dental origin. The lesion was fully excised, and histological examination reported a “common blue nevus.” In this case, we intend to present a rare lesion of the oral cavity and the importance of performing a routine oral examination when given a chance as a preventive approach.

Oral Cancer Stem Cells: Therapeutic Implications and Challenges

Head and neck squamous cell carcinoma (HNSCC) is currently one of the 10 most common malignancies worldwide, characterized by a biologically highly diverse group of tumors with non-specific biomarkers and poor prognosis. The incidence rate of HNSCC varies widely throughout the world, with an evident prevalence in developing countries such as those in Southeast Asia and Southern Africa. Tumor relapse and metastasis following traditional treatment remain major clinical problems in oral cancer management. Current evidence suggests that therapeutic resistance and metastasis of cancer are mainly driven by a unique subpopulation of tumor cells, termed cancer stem cells (CSCs), or cancer-initiating cells (CICs), which are characterized by their capacity for self-renewal, maintenance of stemness and increased tumorigenicity. Thus, more understanding of the molecular mechanisms of CSCs and their behavior may help in developing effective therapeutic interventions that inhibit tumor growth and progression. This review provides an overview of the main signaling cascades in CSCs that drive tumor repropagation and metastasis in oral cancer, with a focus on squamous cell carcinoma. Other oral non-SCC tumors, including melanoma and malignant salivary gland tumors, will also be considered. In addition, this review discusses some of the CSC-targeted therapeutic strategies that have been employed to combat disease progression, and the challenges of targeting CSCs, with the aim of improving the clinical outcomes for patients with oral malignancies. Targeting of CSCs in head and neck cancer (HNC) represents a promising approach to improve disease outcome. Some CSC-targeted therapies have already been proven to be successful in pre-clinical studies and they are now being tested in clinical trials, mainly in combination with conventional treatment regimens. However, some studies revealed that CSCs may not be the only players that control disease relapse and progression of HNC. Further, clinical research studying a combination of therapies targeted against head and neck CSCs may provide significant advances.

PRAME immunohistochemistry is useful in the diagnosis of oral malignant melanoma

OBJECTIVES

While the incidence of cutaneous melanoma has dramatically increased in recent years, oral malignant melanoma (OMM) remains a rare form of noncutaneous melanoma with poor survival. PRAME (PReferentially expressed Antigen in MElanoma) is reported to have diagnostic and some prognostic utility in cutaneous melanomas and some head and neck malignancies. We sought to explore the diagnostic utility of PRAME in OMM.

METHODS

A total of ten specimens from eight unique cases of OMM were identified from the Oral Pathology Biopsy Service (OPBS) at University of Washington School of Dentistry between 2005 and 2019. For all cases, standard histology and immunohistochemistry stains were performed, including a stain against PRAME. The diagnoses were reviewed and confirmed by two pathologists. Clinical and epidemiologic features were described.

RESULTS

Patient ages ranged from 55 to 82. The group consisted of five males and three females. All eight cases were located on the hard palate. Six cases represented invasive melanoma while two were early melanoma in situ. PRAME immunohistochemistry was successfully performed on seven of eight cases: six were positive (86%), one was negative (14%) and one case lacked sufficient tissue for staining.

CONCLUSIONS

Our results suggest that PRAME immunohistochemistry may be useful in the diagnosis of OMM, including early melanoma in situ. Further studies with clinical follow-up and a larger number of cases are needed to explore prognostic value as well as the ability to distinguish between benign, intermediate and malignant melanocytic proliferations of the oral cavity.

Clinicopathological and prognostic value of Ki-67 expression in oral malignant melanoma: A systematic review and meta-analysis

Background. Ki-67 is one of the new biological markers with clinical value in the pathology and prognosis of oral melanoma. It is a nuclear protein involved in regulating cell proliferation. Some studies have suggested an association between Ki-67 and poor survival in patients with oral melanoma. This systematic review was undertaken to clarify this issue. Methods. Databases of PubMed, Scopus, and Web of Science were searched using relevant English keywords from 1988 to April 2022. STATA software version 16 and random models were used for meta-analysis. Results. Eleven articles were included in this systematic review, six of which were selected for meta-analysis. The mean expression of the Ki-67 index in patients with oral melanoma was estimated at 43.81% (28.66‒58.95 with 95% CI, I²=94.2, P<0.001). In addition, the results showed a significant relationship between Ki-67 expression and the prognosis of oral melanoma lesions. Increased expression of this marker weakens the prognosis and decreases the survival rate. Conclusion. High expression of Ki-67 may serve as a predictive biomarker for poor prognosis in patients with malignant oral melanoma. Therefore, classifying this malignancy by Ki-67 expression may be considered for therapy regimen selection and integrated management.

Primary malignant melanoma of mandibular gingiva: A rare case report

Oral malignant melanomas are rare neoplasms of the oral cavity which present significant diagnostic ambiguity. The etiology is unclear though the stimulation of melanoblasts by genetic, epigenetic, and traumatic causes that have been proposed in etiopathogenesis. Clinically, it presents as a pigmented swelling or growth which remains asymptomatic until it advances to later stages. It is highly invasive and metastasizes quickly; hence, it has a very poor prognosis with a survival rate of only 7%. Early diagnosis of the neoplasm and thorough investigation is not only necessary for prompt treatment but also necessary for a favorable prognosis.

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.

Pigmented Oral Lesions: A Multicenter Study

Objectives  The aim of this study was to determine the prevalence and clinical features of pigmented oral lesions from Thailand.

Materials and Methods  Biopsy records of the Department of Oral Pathology, Chulalongkorn University, Department of Oral Diagnosis, KhonKaen University, Department of Oral Biology and Oral Diagnostic Sciences, Chiangmai University, Department of Stomatology, Prince of Songkla University, and Rangsit University were reviewed for oral pigmented lesions diagnosed during 1999 to 2019. Demographic data were culled from the biopsy records. Ages of the patients were subdivided into 10-year intervals. Locations of the lesions were classified as gingiva, labial/buccal mucosa, palate, floor of the mouth, tongue, as well as the combination of sites. Data were analyzed by descriptive statistics using SPSS version 20.0.

Results  Of the 47,175 accessioned cases, 241 cases (0.51%) were diagnosed in the category of pigmented oral lesions. The age of the patients ranged from 1 month to 88 years with the mean ± standard deviation = 38.74 ± 20.96 years. Regarding gender, 172 patients (71.37%) with pigmented lesions were females, while 69 patients (28.63%) were males. The female-to-male ratio was 2.49:1. The majority of the pigmented lesions were encountered at the gingiva (29.88%) followed by labial/buccal mucosa (26.97%), palate (14.94%), lip (10.79%), alveolar mucosa (9.54%), and others (7.88%), respectively. The three most common pigmented oral lesions in the present study were nevus (39.83%), followed by melanotic macule (28.63%) and amalgam tattoo (17.43%), respectively.

Conclusions  The most common pigmented oral lesion in the present study is nevus. Demographic data of the patients in the present study are in accordance with previous studies with minor differences. Even though pigmented lesions of the oral cavity constitute a small portion of the oral pathology biopsies, accurate diagnosis is important since there is an overlap in clinical appearance of benign pigmented lesions and melanoma.

Differential diagnoses of solitary and multiple pigmented lesions of the oral mucosa: Evaluation of 905 specimens submitted to histopathological examination

BACKGROUND

The aim was to analyze the frequency, clinical and demographic features of solitary and multiple/diffuse oral pigmented lesions submitted to histopathological examination, and to summarize the features that guide the clinical differential diagnosis.

METHODS

Clinical and demographic data were retrieved from biopsy records and descriptive statistics were performed.

RESULTS

Nine hundred and five (0.51%) oral pigmented lesions were retrieved among 177 356 specimens, being 95.9% solitary and 4.1% multiple/diffuse lesions. Regardless the overlapping clinical presentation, age, site, association with amalgam restoration, and a nodular appearance may help in the clinical differential diagnosis of solitary oral pigmentations. Patient's habits, site, and systemic signs and symptoms are helpful in the clinical differential diagnosis of multiple/diffuse lesions.

CONCLUSIONS

Oral pigmented lesions are a rare diagnosis in oral pathology and solitary lesions are more commonly submitted to biopsy. Some key features help in the differential diagnosis, though biopsy can be warranted in doubtful cases.

What is the role of the surgeon in the management of head and neck mucosal melanoma in the immunotherapy era?

INTRODUCTION

The advent of immunotherapy has impacted both the management and, to a lesser extent, the outcomes for patients with head and neck mucosal melanoma. As a consequence, one might expect that the role of the surgeon would be limited to the diagnostic work-up and that systemic therapies would be the mainstay of treatment.

METHODS AND RESULTS

Here, we present the surgical aspects of the recently published United Kingdom Head and Neck Mucosal Melanoma Guideline to highlight the continued role of surgeons in the management of this disease. We highlight key areas where surgeons remain the lead clinician and reinforce the multidisciplinary requirement for exemplary patient care.

CONCLUSIONS

Despite the advent of immunotherapy, surgeons continue to have a key role to play in this disease. When indicated, it is essential that appropriate surgery is offered by a suitably experienced team.

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 Malignant Lesion of Central Arch Gingiva of Mandible

Primary oral malignant melanoma (OMM) is a rare malignant lesion with a relatively poor prognosis. The clinical presentation may be nodular, macular, or mixed type, with or without pigmentation. The pigmented lesions in the oral cavity may be either melanocytic or non-melanocytic and neoplastic or non-neoplastic lesions. For all the pigmented lesions of the oral cavity, clinicians must consider OMM as a differential diagnosis. Hence, a histopathological examination is required. Herein, we report a case of pigmented growth over the central arch and gingival mucosa, which turned out to be an OMM.

Oral amelanotic malignant melanoma: a case report

Amelanotic malignant melanoma is an extremely rare and aggressive oral tumor. Herein we report the case of a 42-year-old woman presented with a painful growth in anterior maxillary region. Intra-oral examination showed a non-pigmented exophytic mass occupying the anterior maxillary sector. Incisional biopsy with immunohistochemistry examination revealed a malignant melanoma as it strongly expressed melan A and S-100. Facial computed tomography showed extension to the maxillary bone and hard palate. After thoraco-abdominal computed tomography revealing absence of metastasis, tumor resection was performed respecting 2cm security margin. Oral localization of malignant melanoma is rare especially its amelanotic variant. Lack of pigmentation makes the diagnosis more difficult, usually resulting in treatment delay and making the prognosis even worse. Early detection by histological and immunochemistry examination combined to wide resection are the keys to improving the survival for patients with oral amelanotic melanoma.

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.

Oral malignant melanoma of alveolar ridge

Malignancy of melanocytes, a pigment-producing cell, is referred as malignant melanoma (MM) which occur basically on skin and oral mucous membrane, but as well found in ears, eyes, gastrointestinal tract and genital mucosa. Oral melanomas has propensity to metastasise and invade more voluntarily than other malignant counterparts. Here we present a case of 52-year-old male patient with a chief symptom of blackening of gums in the upper front tooth region. In dental history, the patient revealed history of faulty artificial prosthesis fixed in the same region since 6 months. On the basis of a through clinical assessment, a provisional opinion of oral malignant melanoma, was prepared. On histopathological and immunohistochemical analysis with S-100 and homatropine methylbromide 45 the diagnosis of MM was confirmed.

Oral malignant melanoma of alveolar ridge

Malignancy of melanocytes, a pigment-producing cell, is referred as malignant melanoma (MM) which occur basically on skin and oral mucous membrane, but as well found in ears, eyes, gastrointestinal tract and genital mucosa. Oral melanomas has propensity to metastasise and invade more voluntarily than other malignant counterparts. Here we present a case of 52-year-old male patient with a chief symptom of blackening of gums in the upper front tooth region. In dental history, the patient revealed history of faulty artificial prosthesis fixed in the same region since 6 months. On the basis of a through clinical assessment, a provisional opinion of oral malignant melanoma, was prepared. On histopathological and immunohistochemical analysis with S-100 and homatropine methylbromide 45 the diagnosis of MM was confirmed.

Tongue metastasis of cutaneous melanoma: Report of two cases and literature review

Introduction

Malignant metastases to the oral cavity are rare and metastatic melanomas of the tongue are considered exceptionally uncommon, with less than 10 cases published in the English literature so far.

Case reports

Two female patients in the 7th decade of life presented to our dental service with nodules in the tongue. Both patients had multiple metastases at the time of oral diagnosis and primary melanoma originated on the skin. An intra-oral incisional biopsy was performed under local anesthesia and the histopathologic analysis was characterized by the proliferation of atypical epithelioid cells displaying a poorly delimited cytoplasm and hyperchromatic nucleus which contained eosinophilic macronucleoli. Immunohistochemistry was performed in both cases to confirm the clinical hypothesis of metastatic melanoma. After the diagnosis of oral metastatic melanoma, the patients were maintained under palliative care and close medical follow-up. Both patients died four and a half months and 20 months after the diagnosis of tongue metastasis.

Conclusions

Although rare, metastatic melanoma should be included in the differential diagnosis of tongue lesions detected in patients with a previous medical history of cutaneous melanoma.

Key words:Melanoma, tongue, metástases.

Oral manifestations of a sinus melanoma: case report and literature review

Introduction: Mucosal melanoma (MM) is a rare malignancy of the head and neck. Sinonasal melanomas are the most frequent, followed by oral melanomas. Observation: A 67-year-old patient with a known left sinus melanoma initially treated with immunotherapy was referred for consultation concerning mobile teeth. A pigmented lesion infiltrating the left maxillary arch in the molar area was detected. The malignancy had invaded the oral mucosa. Despite many proposed treatments (immunotherapy, chemotherapy, and radiotherapy), the patient showed metastatic progression, which resulted in death. Discussion: Sinus MMs are malignancies with poor prognosis because these are often diagnosed in the late stages of disease progression. As these tumors are rare, there is no treatment consensus and surgery remains the best option. Diagnosis of pigmented lesions of the oral mucosa is sometimes complicated because of various implied etiologies. Conclusion: This case report shows that sinus MMs can induce pigmentation in the oral mucosa. These are rare malignancies with poor prognosis, for which no treatment consensus exists to date.

Differential Pharmacological Activities of Oxygen Numbers on the Sulfoxide Moiety of Wasabi Compound 6-(Methylsulfinyl) Hexyl Isothiocyanate in Human Oral Cancer Cells

6-(methylsulfinyl) hexyl isothiocyanate (6-MITC) is a naturally occurring compound isolated from Wasabia japonica (wasabi). The synthetic derivatives, 6-(methylsulfenyl) hexyl isothiocyanate (I7447) and 6-(methylsulfonyl) hexyl isothiocyanate (I7557), were derived from 6-MITC with the deletion and addition of oxygen, respectively. We aimed to evaluate the effect of these synthetic compounds on human oral cancer cells, SAS and OECM-1. All three compounds (I7447, 6-MITC, and I7557) inhibited the viability of SAS and OECM-1 cells using MTT assay. Morphological observations showed various proportions of mitotic arrest and apoptosis in cells treated with these compounds. Cell cycle analysis revealed relatively abundant G2/M arrest in 6-MITC and I7557-treated cells, whereas sub-G1 accumulation was found in I7447-treated cells. In using phosphorylated histone H3 as a marker for mitosis, the addition of 6-MITC and I7557 (excluding I7447) could be shown to arrest cells during mitosis. In contrast, I7447 induced more prominent apoptosis than the 6-MITC or I7557 compounds. The down-regulated expression of the phosphorylated form of CHK1 and Cdc25c was noted in 6-MITC and I7557-treated cells. I7557 could sensitize SAS cells to death by radiation. The wasabi compound, 6-MITC, and its chemical derivatives with different numbers of oxygen may have differential pharmacological effects on human oral cancer cells.

KIT, NRAS, BRAF and FMNL2 mutations in oral mucosal melanoma and a systematic review of the literature

Oral mucosal melanoma (OMM) is an aggressive malignant tumor derived from melanocytes in the oral cavity. The genetic etiology of OMM has not been extensively investigated to date. In the present study, the aim was to detect novel gene mutations in patients with OMM. Mutation analysis of KIT, BRAF and NRAS was conducted by polymerase chain reaction. In addition, the relevant literature was searched using the PubMed database, and previous findings were compared with the results of the present study. Among the 9 patients with OMM examined, KIT, BRAF and NRAS mutations were detected, and these mutations were all observed at a frequency of 11.1% (1/9 patients). Notably, a novel FMNL2 mutation in 2 patients with OMM was identified by exome sequencing. In conclusion, the current study observed KIT, BRAF, NRAS and FMNL2 mutations in patients with OMM, which may be of benefit for elucidating the underlying mechanism of OMM pathogenesis.

Loss of nuclear BAP1 expression is associated with poor prognosis in oral mucosal melanoma

Oral mucosal melanoma (OMM) is an aggressive neoplasm with an extremely poor prognosis. BAP1 is a tumor suppressor that has been associated with the outcome of melanomas and other malignancies. In this study, we investigated the genetic alterations in BAP1 and the prognostic potential of BAP1 protein expression in oral mucosal melanoma. DNA sequence analysis of BAP1 from 12 OMM patient samples revealed missense mutations in the tissues from four patients. Based on immunohistochemical staining, loss of nuclear BAP1 expression was associated with poor overall survival (P < 0.001, Log-rank = 21.308) and distant metastasis (P = 0.034, OR = 0.320). Multivariate analysis showed BAP1 to be an independent prognostic factor (P = 0.027, HR = 0.479). It thus appears that loss of nuclear BAP1 expression is an independent prognostic factor of poor overall survival and associated with distant metastasis in OMM.

Palatal Melanoma: "The Silent Killer"

Primary melanoma of the oral cavity is extremely uncommon tumour consisting approximately 0.2 - 8.0% of all melanoma cases and 0.5% of all oral malignancies. It has an aggressive behaviour and poor prognosis, with 5 - year - survival rate between 5 - 20%. The initial symptoms are often unnoticed, which lead to late diagnosis and worsening of the prognosis. Because of its infrequent occurrence, there is no well - defined classification and therapeutic protocol, in contrast to melanomas of another side. Early diagnosis and treatment are essentially linked to survival rate. We present a case of palatal melanoma in a 76 - year - old female patient, as we want to emphasise the importance of the early detection and accurate diagnosis of melanoma of oral cavity, to its influence of the therapeutic outcome.

Longitudinal clinicopathologic data of the progression of oral mucosal melanoma-report of 2 cases and literature review

Oral mucosal melanoma (OMM) is notorious for having a poor prognosis. Recognition of the early features of OMM by both clinicians and pathologists can play an important role in improving survival. Therefore, the purpose of this report is to increase awareness of the early features of OMM, by presenting 2 cases with longitudinal clinical and histopathologic documentation showing progression of OMM from a deceptively bland premalignant (noninvasive) oral melanocytic lesion (POML). By analyzing the clinical and histopathologic features of POML in our cases, and those in the literature, we found that the concerning features are (1) clinically, a pigmented lesion violating the ABCDE criteria or showing multiple recurrences; and (2) histologically, a melanocytic proliferation, in either a lentiginous or pagetoid pattern with or without cellular atypia. Making a diagnosis of POML prospectively is often challenging. Increasing awareness of the clinical and histopathologic features and complete surgical excision of POML are emphasized.

Is focal melanotic lesion potentially malignant? A case report

Malignant melanoma is a lesion of melanocytes that is commonly observed on cutaneous surfaces. In 35–50% of cases, it originates from a pigmented precursor. Although oral melanocytic pigmentation is very common, melanocytic malignancies such as melanoma, are rare. Oral melanoma may arise from pre-existing pigmentation, but definitive precursor lesions have not been identified. Common sites for oral melanoma are the maxillary gingiva and palate. We report a case of malignant melanoma that transformed from a long-standing, focal, pigmented lesion on the mandibular gingiva and vestibular mucosa, suggesting the potentially malignant nature of focal oral melanotic lesions.

Ki67 Proliferation Index as a Histopathological Predictive and Prognostic Parameter of Oral Mucosal Melanoma in Patients without Distant Metastases

Background: To investigate the relationship between clinical and histopathological characteristics and overall survival of patients with oral mucosal melanoma (OMM) without distal metastasis in order to provide predictive prognostic information of OMM.

Methods: Ki67 expression was assessed by immunohistochemistry in 123 patients with OMM without distant metastases. The associations between Ki67 expression and clinical features and overall survival (OS) of patients were statistically analyzed. The Ki67 levels of the primary and recurrent lesions from 14 OMM patients were compared.

Results: Univariate analysis showed that tumor type and cervical lymph node (CLN) status, as well as Ki67 expression, were all correlated with survival. Cox proportional hazards regression analysis identified Ki67 expression and CLN status as independent prognostic factors in OMM patients. Further, we found that Ki67 expression was associated with clinical tumor type of OMM. Moreover, with a cut-off point of 20%, patients with lower Ki67 scores showed a survival advantage over those with higher Ki67 scores.

Conclusions: Ki67 expression may be a useful pathological predictor of survival of OMM patients without distant metastases.

Updates on Immunohistochemical and Molecular Markers in Selected Head and Neck Diagnostic Problems

CONTEXT

- The head and neck regions have complex anatomic structures. They are not exempted from the rare occurrences of highly unusual, diagnostically challenging malignant neoplasms and mimickers.

OBJECTIVE

- To review and update the utility of immunohistochemistry and molecular biomarkers and to pursue diagnostic accuracy on selected rare neoplasms, especially some poorly differentiated malignancies.

DATA SOURCES

- Personal experience and information from the literature.

CONCLUSIONS

- Head and neck tumors include neoplasms originating from heterogeneous tissue. Using the selected clinical cases, this review illustrates a continuous development of emerging molecular-genetic techniques to assist in the interpretation of uncommon, often poorly differentiated, highly malignant neoplasms. The diagnostic results are appropriately transmitted to the oncologists, radiation oncologists, and surgeons to create a coordinated plan of care for patients with these unusual disorders affecting the head and neck.

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.

Primary Oral Melanoma - A Non-Surgical Approach to Treatment via Immunotherapy

INTRODUCTION

Malignant melanoma is an aggressive form of cancer that commonly affects skin and rarely affects the oral cavity. With poorly understood risk factors and an often-asymptomatic presentation, oral melanoma is difficult to detect until advanced stages of disease. Treatment for oral melanomas has been primarily surgical, and survival rates have been low. However, in recent years, immunotherapy has shown much promise with increased patient survival.

CASE PRESENTATION

A 49-year-old male was referred by his primary dentist to a periodontal clinic for management of an alleged unresolved periodontal abscess. The patient had completed full-mouth scaling and root planing and consequently developed a large mass in the left posterior maxilla. Incisional biopsies were performed in multiple locations in the maxillary gingivae, and interpretation revealed atypical melanocytic proliferation and primary melanoma. After appropriate work-up, the patient was treated with two different immunotherapy agents: 1) ipilimumab and 2) pembrolizumab. Results after immunotherapy were favorable, and the tumor significantly decreased in size with no major adverse effects. The response was so strikingly positive that the need for surgical removal was almost eliminated. At the present time, it is unknown whether the patient will receive any surgical treatment barring a recurrence.

CONCLUSIONS

Oral mucosal pigmentation is a finding commonly encountered by dentists during clinical patient examinations. However, proper diagnosis of pigmented lesions, especially those associated with malignancy, requires investigations that go beyond clinical examination.

Primary malignant melanoma

Malignant melanomas (MM) of the oral cavity are extremely rare, accounting for 0.2% to 8.0% of all malignant melanomas. Malignant melanomas is more frequently seen at the level of the hard palate and gingiva. Early diagnosis and treatment are important for reducing morbidity. Malignant melanoma cells stain positively with antibodies to human melanoma black 45, S-100 protein, and vimentin; therefore, immunohistochemistry can play an important role in evaluating the depth of invasion and the location of metastases. A 76-year-old man developed an oral malignant melanoma, which was originally diagnosed as a bluish reactive denture hyperplasia caused by an ill-fitting lower denture. The tumor was removed surgically, and histopathological examination revealed a nodular-type MM. There was no evidence of recurrence over a 4-year follow-up period.

Periodic acid-Schiff-positive loops and networks as a prognostic factor in oral mucosal melanoma

The prognostic factors of oral mucosal melanoma (OMM), a rare and aggressive neoplasm, remain to be determined. The aim of this study is to investigate the prognostic significance of vasculogenic mimicry in OMM. The clinical data of 62 patients with primary OMM treated in Shanghai Ninth People's Hospital from April 2007 to April 2012 were retrieved and analyzed retrospectively. Staining of periodic acid-Schiff (PAS) and CD31 immunohistochemistry were performed to evaluate the prognostic value of PAS-positive patterns, blood lakes, and microvascular density. PAS-positive loops and networks (P<0.001) as well as blood lakes (P=0.040) were found to be predictors of overall survival (OS). The presence of PAS-positive loops and networks was an independent prognostic factor of poor OS in multivariate analysis (P=0.002). Although the presence of PAS-positive loops and networks was associated with hematogenous metastasis (P=0.041) and lymphogenous metastasis (P=0.041), it was not an independent predictor of both types of metastasis in multivariate analysis. Microvascular density was not associated with OS (P=0.627) and metastasis of OMM patients. PAS-positive loops and networks have a significant prognostic value in OMM. Detection of PAS-positive patterns may lead to better staging and serve as a prognostic parameter of OMM.

Clinical value of diascopy and other non-invasive techniques on differential diagnosis algorithms of oral pigmentations: A systematic review

OBJECTIVES

To determine the diagnostic value of diascopy and other non-invasive clinical aids on recent differential diagnosis algorithms of oral mucosal pigmentations affecting subjects of any age.

MATERIAL AND METHODS

Data Sources: this systematic review was conducted by searching PubMed, Scopus, Dentistry & Oral Sciences Source and the Cochrane Library (2000-2015); Study Selection: two reviewers independently selected all types of English articles describing differential diagnosis algorithms of oral pigmentations and checked the references of finally included papers; Data Extraction: one reviewer performed the data extraction and quality assessment based on previously defined fields while the other reviewer checked their validity.

RESULTS

Data Synthesis: eight narrative reviews and one single case report met the inclusion criteria. Diascopy was used on six algorithms (66.67%) and X-ray was included once (11.11%; 44.44% with text mentions); these were considered helpful tools in the diagnosis of intravascular and exogenous pigmentations, respectively. Surface rubbing was described once in the text (11.11%).

CONCLUSIONS

Diascopy was the most applied method followed by X-ray and surface rubbing. The limited scope of these procedures only makes them useful when a positive result is obtained, turning biopsy into the most recommended technique when diagnosis cannot be established on clinical grounds alone. Key words:Algorithm, differential diagnosis, flow chart, oral mucosa, oral pigmentation, systematic review.

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.

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.

Oral malignant melanoma: An aggressive clinical entity - Report of a rare case with review of literature

Melanomais one of the most dreaded and aggressive neoplasms, being derived from epidermal melanocytes. The majority of melanomas are seen to involve the skin, and primary mucosal melanomas account for less than 1% of all melanomas. Oral malignant melanomas (OMM) are asymptomatic at the initial presentation, but later they become painful with growth and expansion. In the late stages, the patient may present with ulceration, bleeding, tooth mobility, paresthesia, ill-fitting prosthesis, and delayed healing of the extraction sockets. Diagnosis is often delayed due to asymptomatic clinical presentation, with silent progression of the lesion. OMM are associated with poor prognosis due to their invasive and metastasizing tendencies. The condition has poor survival rates, and metastatic melanomas show even worse prognosis. The 5-year survival rate for OMM ranges 4.5–29%, with 18.5 months being the mean survival rate. The tumor is best managed by wide surgical resection; however, consideration should also be made for adjunctive therapies such as chemotherapy, immunotherapy, and radiotherapy. Recurrences may be seen even 10–15 years after the primary therapy. This paper aims to present an interesting report of aggressive OMM in a 50-year-old male patient and emphasizes the role of dental professionals in maintaining a high degree of vigilance for the pigmented lesions of the oral cavity. Pigmented lesions of uncertain origin should be routinely biopsied to rule out malignancy. Early diagnosis of this dreadful entity entails thorough history taking, physical examination, and radiographic features coupled with histopathology.

Oral Malignant Melanoma Initially Misdiagnosed as a Racial Pigmentation: A Case Report

Oral malignant melanoma (OMM) is rare, representing less than 0.5% of all oral malignancies. The most affected sites are the palate and the maxillary gingiva. Histological examination is important to establish the diagnosis of any suspicious pigmented lesion in the oral cavity, mainly if a precise clinical diagnosis is not possible. We present one case of OMM that was initially diagnosed as a racial pigmentation elsewhere 2 years earlier. Clinical examination showed multiple macules and nodules located on the hard and soft palate, gingiva and superior alveolar mucosa. These lesions were painless and presented a color variation going from dark blue to black. Histological analysis showed sheets and nests of atypical melanocytes displaying a range of shapes such as plasmacytoid, epithelioid, and round cells, located in the superficial corium extending to the deep tissues. A few tumor cells contained variable amounts of melanin. There was no invasion of blood vessels or nerve fibers. Immunohistochemical analysis revealed that the neoplastic cells were positive for HMB-45, melan-A, S-100 and negative for AE1/AE3, confirming the diagnosis of melanoma. The Ki-67 labeling index was around 25%. The patient refused any treatment and died 11 months later.