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

Oral Melanoma in Older Adults: Epidemiology, Molecular Landscape, and Treatment Strategies

Oral melanoma is an aggressive neoplasm arising from melanocytes in the mucosal epithelium, accounting for 0.2%-0.8% of all melanomas. Unlike cutaneous melanoma, it is not associated with UV exposure, and its pathogenesis involves complex genetic and molecular alterations. This neoplasm predominantly affects older adults (≥ 60 years). Clinically, lesions often present as macular or nodular with an exophytic growth pattern, sometimes ulcerated, and exhibit varied pigmentation. Diagnosis is further complicated by non-pigmented (amelanotic) variants that can resemble other oral pigmentations. Wide surgical excision remains the mainstay treatment, often combined with chemotherapy; however, recurrence and distant metastasis remain high. While immunotherapy has shown promise in other melanoma subtypes, its efficacy in oral melanoma remains uncertain. Treatment in older adults is particularly challenging due to comorbidities and treatment-related morbidity. This review summarizes the epidemiology, clinical features, and current treatment strategies for oral melanoma in older adults. Key advances in the molecular mechanisms underlying this neoplasm are also outlined. As a strategic approach, integrating oral melanoma screening into routine geriatric dental care, supported by diagnostic algorithms, may improve early detection, prognosis, and survival outcomes in this vulnerable population.

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.

Definitive treatment for head and neck mucosal melanoma

Head and neck mucosal melanoma is a rare clinical subtype of melanoma or head and neck cancer. Mucosal melanoma is aetiologically and molecularly distinct from cutaneous melanoma. The therapeutic efficacy of immune checkpoint inhibitors for head and neck mucosal melanoma remains unclear. Surgery is considered as the mainstay of treatment for locally advanced head and neck mucosal melanoma, and adjuvant radiotherapy has a role in local disease control. New treatment modalities, such as targeted therapy and immunotherapy, have changed the treatment of cutaneous melanoma. However, patients with mucosal melanoma have been excluded from most Phase III clinical trials. Due to its rarity, outcome data for locally advanced head and neck mucosal melanoma are scarce and are mainly based on retrospective studies with limited case numbers. The objective of this review was to provide an update and overview of clinical trials, prospective observational studies and retrospective studies and discuss future directions for multimodal treatment of locally advanced head and neck mucosal melanoma.

Metastatic melanoma and rare melanoma variants: a review

The histopathological diagnosis of melanoma is fraught with potential pitfalls. In the setting of cutaneous metastatic melanoma, it is important to recognise the various histological patterns that can be encountered from the more common to the rare, including epidermotropic, folliculotropic, naevoid, and blue naevus-like. In addition, melanoma is notorious for phenotypic plasticity. Thus, there are many different subtypes and cytomorphological variations that can be difficult to recognise as melanoma, particularly in the recurrent or metastatic setting. Select melanoma variants including primary dermal, clear cell, plasmacytoid, signet ring cell, small cell, myxoid, rhabdoid, and dedifferentiated melanoma will be discussed, in addition to composite melanocytic neoplasms. This review is intended to remind the practitioner of key concepts of metastatic disease and select rare melanoma variants, while providing practical guidelines for accurate diagnosis.

Cancer cells co-opt nociceptive nerves to thrive in nutrient-poor environments and upon nutrient-starvation therapies

Although nutrient-starvation therapies can elicit strong anti-tumor effects in multiple carcinomas, it has been convincingly demonstrated that cancer cells exploit the tumor microenvironment to thrive in nutrient-poor environments. Here, we reveal that cancer cells can co-opt nociceptive nerves to thrive in nutrient-poor environments. Initially examining the low-glucose environment of oral mucosa carcinomas, we discovered that cancer cells employ ROS-triggered activation of c-Jun to secrete nerve growth factor (NGF), which conditions nociceptive nerves for calcitonin gene-related peptide (CGRP) production. The neurogenic CGRP subsequently induces cytoprotective autophagy in cancer cells through Rap1-mediated disruption of the mTOR-Raptor interaction. Both anti-glycolysis and anti-angiogenesis-based nutrient-starvation therapies aggravate the vicious cycle of cancer cells and nociceptive nerves and therapeutically benefit from blocking neurogenic CGRP with an FDA-approved antimigraine drug. Our study sheds light on the role of the nociceptive nerve as a microenvironmental accomplice of cancer progression in nutrient-poor environments and upon nutrient-starvation therapies.

Expression sites of immunohistochemistry markers in oral diseases - A scoping review

INTRODUCTION

Immunohistochemistry (IHC) has not always been an easy field for the research beginners like postgraduates, research fellows and scientists. Meaningful interpretation of IHC positivity needs expertise. This could be made easier for beginners by developing a conceptual framework of markers. The literature review revealed a lack of qualitative evidence on the hitherto IHC studies on oral diseases about the overall expression of IHC markers and its comparison with pathology and normal tissues.

AIM

This scoping review aimed to examine the literature and classify the various immunohistochemistry markers of oral diseases based on the tissue, cell and site of expression.

MATERIALS AND METHODS

The review was in accordance with Preferred Reporting Items for scoping reviews (PRISMA -ScR). Electronic databases such as PubMed and Cochrane were searched for relevant articles till 2021.

RESULTS

We included 43 articles. We found five different possibilities of the site of expression of a marker in a cell. They are the nucleus, cytoplasm, cell membrane, extracellular matrix or any of the above combinations. Based on the tissue of expression, we also mapped the markers expressed in oral diseases to their tissue of origin as ectoderm, endoderm, mesoderm and markers with multiple tissues of expression. Based on our results, we derived two classifications that give an overview of the expression of IHC markers in oral diseases.

CONCLUSION

This scoping review derived new insight into the classification of IHC markers based on cell lineage, tissue and site of expression. This would enable a beginner to better understand a marker with its application and the interpretation of the staining in research. This could also serve as a beginner's guide for any researcher to thrive and explore the IHC world.

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.

Mucosal Melanoma: Pathological Evolution, Pathway Dependency and Targeted Therapy

Mucosal melanoma (MM) is a rare melanoma subtype that originates from melanocytes within sun-protected mucous membranes. Compared with cutaneous melanoma (CM), MM has worse prognosis and lacks effective treatment options. Moreover, the endogenous or exogenous risk factors that influence mucosal melanocyte transformation, as well as the identity of MM precursor lesions, are ambiguous. Consequently, there remains a lack of molecular markers that can be used for early diagnosis, and therefore better management, of MM. In this review, we first summarize the main functions of mucosal melanocytes. Then, using oral mucosal melanoma (OMM) as a model, we discuss the distinct pathologic stages from benign mucosal melanocytes to metastatic MM, mapping the possible evolutionary trajectories that correspond to MM initiation and progression. We highlight key areas of ambiguity during the genetic evolution of MM from its benign lesions, and the resolution of which could aid in the discovery of new biomarkers for MM detection and diagnosis. We outline the key pathways that are altered in MM, including the MAPK pathway, the PI3K/AKT pathway, cell cycle regulation, telomere maintenance, and the RNA maturation process, and discuss targeted therapy strategies for MM currently in use or under investigation.

Primary melanoma of the oral cavity: A multi-institutional retrospective analysis in Brazil

Background

Melanoma is an aggressive malignant tumor, rarely observed in the oral cavity. The aim of this study was to describe the clinicopathologic features of a series of oral melanomas.

Material and Methods

A retrospective descriptive study was performed. A total of 15,482 biopsy records from two oral and maxillofacial pathology services in Brazil were analyzed. All cases of oral melanomas were reviewed, and clinical, demographic, histopathological data, treatment, and follow-up status were collected. In addition, immunohistochemistry stains (pan-cytokeratin AE1/AE3, vimentin, α-SMA, CD45, S-100 protein, HMB-45, Melan A, and Ki-67) were performed.

Results

The series comprised of 5 males (71.4%) and 2 females (28.6%), with a mean age of 58.0 ± 9.2 years (range: 45-69 years) and a 2.5:1 male-to-female ratio. The gingiva (n = 3, 42.8%) and hard palate (n = 2, 28.6%) were the most common affected sites, presenting clinically as ulcerated swellings with a brown to black color. Cervical lymph node metastasis was detected in three patients during the first examination. Microscopically, 6 cases (85.7%) were melanotic, and one (14.3%) was amelanotic. Most cases (n = 4, 57.1%) presented a predominance of epithelioid cells. S-100 and HMB-45 were positive in all cases (n = 7, 100.0%). In contrast, only 4 cases (57.1%) were positive for Melan-A. The proliferative index with Ki-67 was high, with labeling index ranging from 70.0% to more than 90% of positive cells. Five patients died from complications of the tumors after a mean follow-up period of 7.8 months.

Conclusions

Melanoma is an aggressive malignant tumor that rarely occurs in the oral cavity. It occurs mainly in adult and elderly patients and often is diagnosed in advanced stages. The current findings were similar to previous studies and reflected the characteristics of the services from where lesions were retrieved.

Key words:Head and neck cancer, melanoma, oral melanoma, oral mucosa.

Oral pigmented lesions: a retrospective analysis from Brazil

Background

Pigmented lesions are uncommon in the oral mucosa, and studies investigating the incidence and types of these lesions are desired to improve the diagnostic knowledge of clinicians. The aim of this study was to analyze the distribution of oral pigmented lesions in a Brazilian population.

Material and Methods

A retrospective descriptive cross-sectional study was performed. Oral pigmented lesions were retrieved from the files of two oral and maxillofacial pathology services from Brazil over a 45-year period (1974-2019). The clinical data and the diagnoses of each case were retrieved and included in a Microsoft Excel® database.

Results

From 77.074 lesions diagnosed in this period, 761 (0.99%) represented pigmented lesions of the oral mucosa, including 351 (46.1%) melanocytic and 410 (53.9%) non-melanocytic lesions, with a higher incidence in females (73.2%) between the fourth and seventh decades of life. Amalgam tattoo (53.6%) represented the most common lesion, followed by melanotic macule (18.3%) and racial pigmentation (10.8%). Other pigmented lesions included nevus (9.9%), post-inflammatory pigmentation (3%), melanoma (2.1%), melanoacanthoma (1.4%), smoker's melanosis (0.4%), drug-induced pigmentation (0.3%), and melanotic neuroectodermal tumor of infancy (0.1%). The buccal mucosa was the most commonly affected site (25.2%), followed by the alveolar ridge (14.5%), and gingiva (11.8%).

Conclusions

The current findings were similar to previous studies with minor differences due methodology and characteristics of the services from where lesions were retrieved. The knowledge of these data may contribute to a better understanding of oral pigmented lesions and assist clinicians to better recognize and manage them.

Key words:Pigmented lesions, pigmentation, melanin, amalgam, oral cavity.

Oral Amelanotic Melanomas: Clinicopathologic Features of 8 Cases and Review of the Literature

Mucosal melanomas are aggressive tumors, rarely observed in the oral cavity. The diagnosis is based on the clinical and microscopical features. Often these tumors had variable amounts of melanin pigmentation. However, when melanin is absent, the tumors are denominated amelanotic, presenting a tendency to misdiagnosis and delayed treatment. The aim of this study was to describe the clinicopathologic features of a series of oral amelanotic melanomas (OAM). Records of all cases of OAM were retrospectively retrieved from oral pathology services from January 2002 to January 2019. Data regarding the clinical features, morphological aspects, immunohistochemical reactions, treatment, and follow-up status were collected. Eight cases of OAM were included, 6 in men and 2 in women (ratio of 3:1) ranging in age from 33 to 77 years (mean 53.6 years). Clinically, the tumors presented as masses or ulcerated swellings. The most common intraoral locations of the tumors were gingiva and palate. Cervical lymph node metastasis was detected in 3 patients at the first examination. All but one patient died from complications of the tumors after a mean follow-up period of 8.5 months. In conclusion, OAM is a very aggressive malignant tumor, and when melanin is absent, an immunohistochemical panel comprising S100, melan A, HMB45, and SOX10 should be performed.

Multifocal Amelanotic Melanoma of the Hard Palate: A Challenging Case

Among all melanomas, the mucosal type is very rare and may occur in the sino-nasal mucosa, vagina, anus and the oral cavity. At variance with melanomas of the skin, no risk factors, such as familiarity, UV-exposure and skin phenotype, have been clearly identified for such neoplasms. Frequently, the diagnosis is delayed and achieved at advanced stages or when metastases have already occurred. The authors report on a case of mucosal melanoma of the oral cavity presenting as a mass of the hard palate in a 50-year old male, and the corresponding diagnostic-therapeutic pathway.

Oral melanomas in HIV-positive patients: Report of two cases and review of the literature

Oral melanoma in HIV-positive patients is exceedingly rare, with only two cases reported in the literature published in English. Herein, we report two additional cases of oral melanomas which occurred as oral masses in the upper gingiva and hard palate in 35- and 27-year-old HIV-positive women. Significant thrombocytopenia, anemia, reduced CD4 cells, and high HIV load occurred in both patients. Microscopically, the lesions showed a variable proliferation of fusiform and epithelioid-pigmented cells, with cellular pleomorphism and high mitotic index. The diagnosis of melanoma was supported by positive immunoreactivity for S-100, MelanA, and HMB-45. Both cases had an unfavorable outcome, and the patients died a few months after the initial diagnosis. Because of its rarity, oral melanoma occurring in HIV-positive patients can pose problems in diagnosis and should be clinically distinguished from Kaposi's sarcoma, which is more common in the context of the immunodeficiency syndrome.

Expression of mitochondrial dynamics markers during melanoma progression: Comparative study of head and neck cutaneous and mucosal melanomas

BACKGROUND

Head and neck mucosal melanomas (MMs) are rare tumors with adverse outcomes and poorer prognoses than their more common cutaneous counterparts (cutaneous melanomas-CMs). Few studies have compared the expression of mitochondrial dynamic markers in these tumors. This study aimed to assess the correlations of mitochondrial markers with melanoma progression and their potential as predictors of lymph node involvement and distant metastasis.

METHODS

Immunohistochemistry against anti-mitochondrial (AMT), dynamin-related protein 1 (DRP1), mitochondrial fission protein 1 (FIS1), mitofusin-1 (MFN1), and mitofusin-2 (MFN2) antibodies was performed in 112 cases of head and neck CM and MM. A Cox regression multivariate model was used to assess the correlation of AMT, FIS1, and MFN2 expressions considering the risk for nodal and distant metastasis.

RESULTS

All markers studied presented higher staining in tumor cells than normal adjacent tissues. Higher mitochondrial content was observed in MM than in CM, and it was significantly associated with nodal metastasis in oral melanomas. Both FIS1 and DRP1 expressions were related to advanced Clark's levels in CM, and they were overexpressed in oral melanomas. Moreover, increased immunoexpression of MFN2 was significantly associated with a higher risk of metastasis in CM, and it was also overexpressed in sinonasal melanomas.

CONCLUSIONS

Our results suggest that mitochondrial fission and fusion processes can play an important role during multiple stages of tumorigenesis and the development of nodal and distant metastasis in cutaneous and mucosal melanomas.

Phosphorylated Akt1 expression is associated with poor prognosis in cutaneous, oral and sinonasal melanomas

Melanomas are highly aggressive tumours derived from melanocytes, which occur most commonly in the skin. Occasionally, these tumours may appear in oral and sinonasal mucous membranes. In this study, we performed a comparative analysis of the Phosphorylated Akt1 (p-Akt1) expression in 144 patients affected by cutaneous (CM), 34 oral cavity (OM), and 31 sinonasal melanomas (SNM). Similar to the metastatic cutaneous melanomas, p-Akt1 was overexpressed in 17/34 of the oral cavity and 20/31 of the sinonasal melanomas. In addition, the p-Akt1-nuclear expression was associated with poorer cancer-specific survival in cutaneous (P < .0001), oral (P < .0001), and sinonasal (P = .001) melanomas. Multivariate analysis showed p-Akt1 to be an independent prognostic marker in oral (P = .041) and sinonasal (P < .0001) melanomas patients. In conclusion, p-Akt1 overexpression is an independent prognostic marker in mucosal melanomas and is significantly up-regulated in sinonasal melanomas. As both mucosal and metastatic cutaneous melanomas showed high frequency of p-Akt1 expression, these findings suggest that mucosal melanomas have a biological behaviour, similar to the aggressive cutaneous melanomas.

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.

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.

Immunohistochemical expression of cyclooxygenase-2 (COX-2) in oral nevi and melanoma

BACKGROUND

Cyclooxygenase-2 (COX-2) catalyses the conversion of arachidonic acid to prostaglandin, and its overexpression has been demonstrated in different malignant tumors, including cutaneous melanoma. However, no data about the expression of this protein in oral melanocytic lesions are available to date. The aim of this study was to evaluate the immunohistochemical expression of COX-2 in oral nevi and melanomas, comparing the results with correspondent cutaneous lesions.

METHODS

COX-2 was evaluated by immunohistochemistry in 49 oral melanocytic lesions, including 36 intramucosal nevi and 13 primary oral melanomas, and in four cutaneous nevi and eight melanomas.

RESULTS

All cases of oral and cutaneous melanomas were positive for COX-2. On the other hand, all oral and cutaneous melanocytic nevi were negative.

CONCLUSION

COX-2 is highly positive in oral melanomas and negative in oral nevi and might represent a useful marker to distinguish melanocytic lesions of the oral cavity.

Certainty of S100 from Physiology to Pathology

S100 exists in wide variety of tissues and cell types, originally isolated from brain tissue and they are of low molecular weight proteins. S100 is evenly distributed in cytoplasm and also in nucleoplasm and is involved in both intercellular and extracellular functions. S100 protein is generally expressed in normal and also in pathological conditions. In current review, we discuss: a) update nomenclature of the various S100 proteins, b) expression of S100 in oral diseases (different soft tissue tumors, odontogenic cyst and tumor) for diagnostic value and also to know their histogenesis, c) role of S100 and RAGE receptor in oral squamous cell carcinoma.

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.

Local anesthetic thoracoscopy for the diagnosis of metastatic pleural melanoma originated from oral malignant melanoma: case report and comments

BACKGROUND

Oral malignant melanoma (OMM) is an aggressive tumor with very low survival rate and easy to metastasize. Pleural metastatic melanoma via primary OMM is rare.

CASE PRESENTATION

In this report, we presented a case of metastatic malignant melanoma of the pleura originated from OMM. A 54-year-old man without primary skin lesion was diagnosed multiple nodular shadows, pleural invasion, and pleural effusion by chest computed tomography (CT). One cyst-form tumor on the tongue base was observed by bronchoscopy, which was diagnosed as OMM by pathological examination and then was resected. After getting the tumor tissues from the pleura by pleural biopsy surgery, the diagnosis of pathological examination was pleural metastatic melanoma. Furthermore, tumor cells displayed a positive immunoreaction for melanocytic markers S100 and HMB-45 combining with positive vimentin and cytokeratin AE1/AE3. The patient was therefore diagnosed with metastatic melanoma of the left pleura and the primary melanoma was OMM.

CONCLUSIONS

According to this case, we could draw the conclusion that pleural metastasis from OMM was very rare and thoracoscopy preceded under local anesthesia is an important method for its accurate diagnosis.

Amelanotic Melanoma Presenting with Plasmacytoid Morphology and BRAF V600 Mutation

Plasmacytoid melanoma is an unusual variant of malignant melanoma. The plasmacytoid morphology can be found in a variety of other malignancies including carcinomas, plasma cell neoplasms, lymphoproliferative disorders, and sarcomas. The authors report a rare case of plasmacytoid amelanotic malignant melanoma in a 78-year-old man presenting with an enlarging palpable, erythematous mass on his left posterior shoulder. A fine needle aspirate showed atypical findings with single amelanotic cells with high nuclear to cytoplasmic ratio, mono- and multi-nucleation with prominent nucleoli and intranuclear inclusions. Review of the excision and immunohistochemical analysis revealed the malignant plasmacytoid cells stained with vimentin, S-100, HMB-45, and other staining patterns consistent with melanoma. Initial evaluation was negative for other sites of disease. However, 4 months later, the patient was noted to have metastatic disease to his lungs and liver. Given that the tumor was noted to be BRAF V600R mutated, the patient was started on single agent dabrafenib. The plasmacytoid morphology can be found in a variety of malignancies. Melanoma should be considered in the differential diagnosis of any malignancy presenting with plasmacytoid features.

Primary amelanotic mucosal melanoma of the oronasal region: report of two new cases and literature review

Primary amelanotic mucosal melanoma is a rare entity with challenging histopathological features. Because these tumors are thought to be biologically more aggressive, they have a poorer prognosis than that of pigmented melanomas. In this work, we present a literature review about the clinical, histopathological, and immunohistochemical features of primary amelanotic mucosal melanoma of the oronasal region and report two new cases. Amelanotic mucosal melanoma commonly affects men in the seventh decade of life and tend to have a poor prognosis, as seen by the high incidence of metastasis, recurrences, and, ultimately, death. There is a similar pattern in the clinic-pathological predilections (such as age, gender, primary site, and metastatic potential) of amelanotic mucosal melanoma when comparing with data reported for pigmented lesions. This work reinforces knowledge about amelanotic mucosal melanomas and epidemiologic predilections. The optimal management of this lesion remains controversial.

Clinicopathological characterization of primary oral and sinonasal melanoma in a referral centre in Mexico City: 2000-2012

In Mexico, there have been few studies on primary oral and sinonasal melanoma, an aggressive neoplasm with a low survival rate and few therapeutic alternatives. Further, there is limited information about its clinical and histopathological characteristics. The aim of this retrospective study was to describe the clinicopathological profile of these tumours in patients attending a major oncology reference centre in Mexico City over a 12-year period. Demographic and clinical data were obtained from the clinical charts, and histopathological features were evaluated. χ(2), Fisher's exact, and Mann-Whitney U-tests were used for analysis; significance was set at P<0.05. Thirty-three cases were studied (73% sinonasal melanoma (SNM) and 27% oral melanoma (OM)); 58% were female and the median age was 66 (Q1-Q3 55.5-75) years. Compared with OM patients, SNM patients had a shorter time to diagnosis (16.7 vs. 11.7 months, P=0.022), were identified at earlier stages (33.3% vs. 58.3%, P=0.010), and all presented symptoms (66.7% vs. 100%, P=0.015). All samples showed vertical growth and 96.9% exhibited pleomorphism. A higher proportion of cases with pleomorphism developed metastases at follow-up than those without (60% vs. 12.5%, P=0.026). The present study provides valuable information that could form the basis of future studies in the search for advanced therapy modalities.

Gastric metastases from invasive primary mucosal epithelioid malignant melanoma of the hard palate: report of the first case in the English literature

Melanocytes arise from the neural crest and migrate to the epidermis, meninges, uveal tract and ectodermal mucosa. Normal gastric mucosa lacks melanocytes. A 64-year-old woman presented to us with nausea and vomiting. She had a past history of invasive primary mucosal epithelioid malignant melanoma of the hard palate 21 months ago, treated by a wide surgical excision. Gastroscopy revealed multiple punched out ulcers involving the stomach and the first part of duodenum. Immunohistology and clinicopathologic correlation established the diagnosis of metastatic gastric malignant melanoma. To our knowledge, this is the first report in the English literature about gastric metastases arising from primary palatal mucosal melanoma.