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

Primary Sinonasal Mucosal Melanoma: A Narrative Review

Mucosal melanomas (MMs) are under-researched tumors with a poor prognosis that arise from melanocytes found in the mucous membranes at different anatomical locations throughout the body. MMs are an uncommon yet highly aggressive tumor that typically develops on mucosal surfaces, predominantly in the head and neck region. MM of the head and neck occurs in 8-10% of all head and neck melanomas. It most commonly affects the mucosa of the nasal cavity and paranasal sinuses (75%), followed by the oral cavity mucosa (25%). A family history and the presence of mucosal nevi are associated with the occurrence of MM. Inhaled and dietary carcinogens are also linked to the development of sinonasal melanoma, much like other malignancies of the nasal cavity. Overexpression of the C-KIT gene is found in more than 80% of all primary mucosal melanomas, with somatic mutations in 10-30% of cases. The presence of these genetic alterations is also reflected in recent clinical studies of specific gene inhibitors that have proven efficiency in the systemic therapy of melanoma. There are various treatment modalities for MM. Surgical therapy involves en bloc surgical resection with a macroscopically visible and palpable mucosal margin of 1.5-2 cm. Partial resection of the maxilla may be considered if it ensures adequate tumor-free margine. Because of its rarity, outcome data for locally advanced head and neck MM is limited and primarily derived from retrospective studies with small case numbers. This review aims to update and summarize findings from clinical trials, prospective observational studies, and retrospective studies, while also exploring future directions for multimodal treatment approaches in this area.

Malignant Melanoma of the Tongue: A Scoping Review

Malignant melanoma of the tongue is a rare and highly aggressive neoplasm, constituting less than 2% of oral melanomas. Due to its rarity and atypical clinical presentation, diagnosis and management pose significant challenges. This study provides a scoping review of research on melanoma of the tongue to determine the available data on the epidemiology, clinical features, histopathological characteristics, treatment strategies, and outcomes of this malignancy. Our literature search identified papers published from 1941 to 2024, and 47 individual cases were analyzed. The mean age at diagnosis was 58.6 years, with a male predominance (58.1%). Lesions were most frequently located on the body and lateral borders of the tongue. A high percentage (38.5%) presented with distant metastases at diagnosis, commonly involving the lungs and brain. Histopathological examination highlighted spindle cell morphology in many cases, with immunohistochemical markers such as HMB-45 and S-100 proving essential for diagnosis. Wide local excision with or without neck dissection was the primary treatment, though recurrence rates remained high (20.5%). Despite aggressive management, overall outcomes were poor, reflecting the melanoma's advanced stage at diagnosis in most cases. This scoping review underscores the need for heightened clinical suspicion, particularly for pigmented or ulcerative lesions of the tongue. Early diagnosis, multidisciplinary management, and further research into the genetic and molecular mechanisms underlying tongue melanoma are crucial to improve outcomes for this rare and aggressive disease.

Amelanotic Melanoma: A Rare Sinonasal Malignancy

Mucosal melanomas account for less than 1% of all sinonasal malignancies and are aggressive tumours originating from melanocytes in various mucosal epithelia. Diagnosis is often delayed due to nonspecific symptoms, contributing to challenges in treatment and management. We present a case of a 75-year-old female with epistaxis and nasal blockage, ultimately diagnosed with amelanotic sinonasal melanoma. Despite diagnostic difficulties exacerbated by profuse bleeding during biopsy attempts, a comprehensive approach involving clinical evaluation, imaging, and histopathology led to a definitive diagnosis. Immunohistochemistry played a crucial role in confirming the diagnosis, ruling out differential diagnoses such as olfactory neuroblastoma and lymphoma. Surgical excision, despite intraoperative bleeding, was successful, followed by adjuvant chemotherapy and radiotherapy due to the tumor's advanced stage. The case underscores the importance of a multidisciplinary approach and personalized treatment strategies, considering the tumor's molecular characteristics for improved outcomes in managing this rare malignancy.

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.

Clinicopathological Features of 26 Intraoral Polymorphous Adenocarcinomas from a Single Brazilian Institution

PURPOSE

This study describes a large, well-documented case series of salivary gland polymorphous adenocarcinomas (PAC) from a single Brazilian center.

METHODS

Demographic data, clinical presentation, histopathological and immunohistochemical features from 26 cases of PAC were analyzed and discussed in detail.

RESULTS

Most patients were females (n = 21), with a ratio of 1:4.2 (male: female) with a mean age of 58.8 years (ranging from 36 to 84 years). The most common clinical presentation was a fibrocollagenous, firm nodular lesion, with a mean size of 2.46 cm (ranging from 0.5 to 3 cm). Most lesions occurred on the palate (n = 16), followed by buccal mucosa (n = 3), upper lip (n = 3), buccal vestibule (n = 2) and alveolar ridge (n = 1). Histologically, various growth patterns were observed, including tubular, solid, cribriform, papillary, and cystic. Additionally, glomeruloid slit-like structures, mucous, and clear cells were noted. Surface papillary epithelial hyperplasia was observed in a few cases. Nine cases exhibited myxoid and collagenous areas, while two cases showed fusiform areas and another case demonstrated squamous differentiation. Clear cell predominance was noted in two cases, and peri- and intraneural invasion was seen in eight cases. Immunohistochemical analysis revealed positivity for S-100, p63 and CK7, and negativity for p40 in all cases. The Ki-67 proliferation index was markedly low in most cases, with a mean of 2.5%.

CONCLUSION

We have provided a broad, detailed description of the clinical and microscopic features of PAC in a large, Brazilian cohort. These findings, in a resource-limited area, may be quite useful for establishing a proper diagnosis.

Challenges in the Diagnosis and Treatment of Oral Amelanotic Malignant Melanoma: A Case Report

Oral malignant melanoma (OMM) is extremely rare and usually has a poor prognosis. Early diagnosis is very important and can improve survival but it is usually difficult due to a lack of symptomatology. We present the first case of a 39-year-old East European woman with oral amelanotic melanoma, who underwent surgery and adjuvant immunotherapy; however, after six months, she developed local recurrence. The patient continued immunotherapy with external radiotherapy targeting the oral tumor recurrence. During therapy, imagistic reevaluation brought evidence of bones, lungs, liver, endotracheal, and brain metastases. Histological differential diagnosis between amelanotic OMM and leiomyosarcoma was necessary to establish the right course of treatment. A series of complications further delayed chemotherapy administration, making the treatment in this case very challenging. The patient had a significant, although late response to immunotherapy, and maintained a good performance status during disease progression with a survival of 15 months until present.

Primary Nasopharyngeal Melanoma without invasive and Metastasis: A Rare Case Reports and Literature Reviews

Objective: Nasopharyngeal melanoma is a rare mucosal malignant melanoma with high recurrence rate, metastasis rate and vascular invasion rate. In this paper, we report a case of primary nasopharyngeal mucosal melanoma. Methods: A case of primary nasopharyngeal mucosal melanoma was reported, and its clinical symptoms, pathological characteristics, treatment and follow-up were described in detail. Results: This report describes a 59-year-old male patient with persistent nasal congestion and suspected malignant nasopharyngeal neoplasm. Patients receive surgical resection and adjuvant radiotherapy after complete resection. Imaging studies showed no tissue invasion or lymph node metastases. The results of immunohistochemistry were Melan-A(+), HMB45(+), and S100(+). The final diagnosis was malignant nasopharyngeal melanoma. After 2 years of follow-up, the prognosis was good, and there was no metastasis or recurrence. Discussion: Nasopharyngeal melanoma is a rare malignancy with a poor prognosis, and surgical resection is the mainstay of treatment. Postoperative adjuvant therapy can improve the rate of local control of lesions. Early diagnosis and thorough examination are extremely important for the patient's prognosis.

Diagnosing Cutaneous Melanocytic Tumors in the Molecular Era: Updates and Review of Literature

Over the past decade, molecular and genomic discoveries have experienced unprecedented growth, fundamentally reshaping our comprehension of melanocytic tumors. This review comprises three main sections. The first part gives an overview of the current genomic landscape of cutaneous melanocytic tumors. The second part provides an update on the associated molecular tests and immunohistochemical stains that are helpful for diagnostic purposes. The third section briefly outlines the diverse molecular pathways now utilized for the classification of cutaneous melanomas. The primary goal of this review is to provide a succinct overview of the molecular pathways involved in melanocytic tumors and demonstrate their practical integration into the realm of diagnostic aids. As the molecular and genomic knowledge base continues to expand, this review hopes to serve as a valuable resource for healthcare professionals, offering insight into the evolving molecular landscape of cutaneous melanocytic tumors and its implications for patient care.

Small Round Blue Cell Tumours of the Sinonasal Area: Our 5 year Experience in a Tertiary Care Centre in India

Purpose: The main purpose of this study is to understand the characteristics and management of sinonasal small round blue cell tumors and also to emphasise the role of immunohistochemistry in their diagnosis and on the outcomes after endoscopic/open excision in these patients. Methods: This is a retrospective study conducted at a tertiary care referral centre in India which included 38 patients with sino nasal for a period of 5 years. All the patients were evaluated clinically and radiologically. All cases were confirmed diagnostically with histopathological examination and immunohistochemistry following surgical excision either by endoscopic or open approach. Some of the cases underwent post operative radiotherapy. Results: In our study, among 176 cases diagnosed with Sino nasal malignancies, 38 (21.6%) cases were diagnosed with sinonasal small round blue cell tumors with male to female ratio 1.4:1. Most common histopathological type among all the sinonasal small round blue cell tumors that presented to us was esthesioneuroblastoma i.e., 8 (21%) patients followed by pituitary macroadenoma in 7(8.4%) patients. Other types are undifferentiated squamous cell carcinoma 10(13.1%), craniopharyngioma 8(10.5%), lymphoma 3(7.9%), synovial/spindle cell sarcoma, malignant melanoma and adenocarcinoma 1(2.6%) each. Schwannoma, rhabdomyosarcoma, neuroendocrine carcinoma and neurofibroma 2 (5.2%) each. Conclusion: Sinonasal small round blue cell tumors are extremely rare tumours. Histopathological diagnosis with immunohistochemistry is characteristic of various tumors and is conclusive for diagnosis. Knowledge of these tumor entity is essential as early diagnosis helps in further management in preventing spread to vital structures and improving outcome. Most of the tumors have a multimodality treatment approach which includes surgical excision, radiotherapy and chemotherapy.

The human and animals' malignant melanoma: comparative tumor models and the role of microbiome in dogs and humans

Currently, the most progressively occurring incident cancer is melanoma. The mouse is the most popular model in human melanoma research given its various benefits as a laboratory animal. Nevertheless, unlike humans, mice do not develop melanoma spontaneously, so they need to be genetically manipulated. In opposition, there are several reports of other animals, ranging from wild to domesticated animals, that spontaneously develop melanoma and that have cancer pathways that are similar to those of humans. The influence of the gut microbiome on health and disease is being the aim of many recent studies. It has been proven that the microbiome is a determinant of the host's immune status and disease prevention. In human medicine, there is increasing evidence that changes in the microbiome influences malignant melanoma progression and response to therapy. There are several similarities between some animals and human melanoma, especially between canine and human oral malignant melanoma as well as between the gut microbiome of both species. However, microbiome studies are scarce in veterinary medicine, especially in the oncology field. Future studies need to address the relevance of gut and tissue microbiome for canine malignant melanoma development, which results will certainly benefit both species in the context of translational medicine.

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.

Primary mucosal melanoma of the larynx: systematic review of the literature and qualitative synthesis

PURPOSE

Primary mucosal melanoma of the larynx (PLM) is a rare entity among head and neck cancers. Due to its rarity, clear protocols of management are not available. A deeper knowledge of the clinical and biological behaviour of PLM is strongly needed.

METHODS

According to PRISMA process, we searched through electronic databases case reports, case series and review articles providing relevant clinical data. The survival analysis was performed with Kaplan-Meier survival curves, using disease free survival (DFS) and overall survival (OS) as endpoints.

RESULTS

1074 articles were initially screened, of which 37 studies describing 44 PLM cases were selected and included in the analysis. Mean age was 59.7 years with a mean follow-up time of 25.4 months. The most common symptom at presentation was hoarseness (52%), while the most involved laryngeal subsite was supraglottic region (62%). Most patients presented with an advanced stage. Tumour (T) and node (N) status at presentation did not influence OS nor DFS, whereas distant metastases (M) status resulted significantly associated with the reduction of OS and DFS time (Mantel-Cox: p < 0.0001 and p = 0.001, respectively). The laryngeal subsite and the type of surgery performed did not significantly impact on OS and DFS.

CONCLUSIONS

Treatment for PLM remains debated. Surgery with safe margins is recommended due to the high rates of local recurrence. Systemic therapy is advised for metastatic disease. However, the prognosis remains poor even after radical resection or targeted therapy.

Oral Malignant Melanoma

To present a case of malignant melanoma. A 55-year old female presented with swelling over left upper gingiva which bled on brushing. She was diagnosed with left oral malignant melanoma on histopathology of punch biopsy specimen, which was then followed by C.T. P.N.S and Neck to know the lesion's extent and Ultrasonography of Abdomen and Pelvis to rule out any metastatic deposits. Patient was managed by left lower partial maxillectomy with left radical neck dissection. No intra-operative or post-operative complications seen. Patient was then sent for chemoradiotherapy. No any complications seen at fifteen months follow-up. Oral malignant melanoma is amenable to surgery and chemoradiotherapy with excellent results if detected at an early stage.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-021-02735-1.

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.

Oral Amelanotic Melanoma: A Systematic Review of Case Reports and Case Series

Oral amelanotic melanoma (OAM) is a rare, non-pigmented mucosal neoplasm representing less than 2% of all melanoma. The present study analyses the available data on OAM and describes its clinicopathological features, identifying potential prognostic factors. Online electronic databases such as PubMed-Medline, Embase, and Scopus were searched using appropriate keywords from the earliest available date till 31st March 2021 without restriction on language. Additional sources like Google Scholar, major journals, unpublished studies, conference proceedings, and cross-references were explored. 37 publications were included for quantitative synthesis, comprising 55 cases. The mean age of the patients was 59.56 years, and the lesions were more prevalent in males than in females. OAM's were most prevalent in the maxilla (67.2%) with ulceration, pinkish-red color, nodular mass, and pain. 2 patients (3.36%) were alive at their last follow-up, and 25 were dead (45.4%). Univariate survival analysis of clinical variables revealed that age older than 68 years (p = 0.003), mandibular gingiva (p = 0.007), round cells (p = 0.004), and surgical excision along with chemotherapy & radiation therapy (p = 0.001) were significantly associated with a lower survival rate. Oral Amelanotic Melanoma is a neoplasm with a poor prognosis, presenting a 6.25% possibility of survival after 5 years. Patients older than 68 years, lesions in the mandibular gingiva, round cells, and surgical excision along with chemotherapy and radiotherapy, presented the worst prognosis. However, they did not represent independent prognostic determinants for these patients.

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.

Clinical features, molecular characteristics and surgical management of primary penile mucosal melanoma based on the European Association of Urology Penile Cancer Guidelines

Penile mucosal melanoma is an aggressive and rare genital malignancy. The aim of the present study was to review the management and outcomes of a homogenous cohort of patients with histologically confirmed penile mucosal melanoma, at a single specialist centre. A retrospective review of an institutional database identified patients with penile mucosal melanoma over a 10-year period. Patient demographics, histopathological characteristics, type of primary surgery, recurrence, presence of metastatic disease and molecular markers were evaluated. The management of the patients was initially based on the European Association of Urology (EAU) penile cancer guidelines which are primarily for squamous cell carcinoma with inputs from a melanoma multidisciplinary team. Twelve patients with penile mucosal melanoma were analysed. Median [interquartile range (IQR)] age was 69.5 (67.25-81) years. The overall median follow-up (IQR) was 69.5 (20-114) months, while median follow-up for cancer-specific survival (CSS) was 11.5 (8-37) months. Location of the primary tumour was glans penis (n = 7), urethra (n = 2) and inner prepuce (n = 3). The CSS at 1, 2 and 5 years after primary surgery was 33%, 16.7% and 0%, respectively. The recurrence-free survival at 1, 3 and 5 months after the primary surgery was 90%, 67% and 56%, respectively. All patients with metastatic disease or with inguinal lymph node invasion at presentation, died within 25 months of the primary diagnosis. Management based on the modified EAU penile cancer guidelines still led to poor outcomes. We present a management diagram based on our experience.

Sinonasal Mucosal Melanoma: A Population-Based Comparison of the EUROCARE and SEER Registries

Introduction  Sinonasal melanomas are rare tumors with no comparative survival studies between Europe and the US.

Objective  To provide a population-based survival analysis between the two continents.

Methods  The European Cancer Registry (EUROCARE) and the United States Surveillance, Epidemiology, and End Results (SEER) databases were queried to identify patients diagnosed with sinonasal melanoma between 2000 and 2007. Relative survival (RS) data were grouped by age, gender, geographic region, extent of disease, and treatment modality.

Results  A total of 1,294 cases were identified between 2000 and 2007 (935 from EUROCARE-5 and 359 from SEER). Females were most commonly identified in Europe (56.4%) and in the US (54.9%). Patients over the age of 65 years comprised the greatest proportion of patients in Europe (70%) and in the US (71%). By region, Southern Europe had the highest 5-year RS (31.6%, 95% confidence interval [CI] = [21.3–42.5%]), and Eastern Europe the lowest (16.5%, [7.5–28.5%]). The aggregate European 5-year RS was 25.4% [21.8–29.1%] and the U.S. was (29.7%, [23.6–36%]).

Conclusions  Although increasing in incidence, sinonasal melanomas remain rare. Women were more commonly affected. The most common age group was those older than 65 years, although age did not confer a prognostic value. The most common subsite was the nasal cavity followed by the maxillary sinus. Five-year RS was similar between continents with an inverse relationship between extent of disease and survival. The treatment of choice throughout Europe and the US remains primarily surgical.

Canine Oral Melanoma Genomic and Transcriptomic Study Defines Two Molecular Subgroups with Different Therapeutical Targets

Simple Summary

In humans, mucosal melanoma (MM) is a rare and aggressive cancer. The canine model is frequently and spontaneously affected by MM, thus facilitating the collection of samples and the study of its genetic bases. Thanks to an integrative genomic and transcriptomic analysis of 32 canine MM samples, we identified two molecular subgroups of MM with a different microenvironment and structural variant (SV) content. We demonstrated that SVs are associated with recurrently amplified regions, and identified new candidate oncogenes (TRPM7, GABPB1, and SPPL2A) for MM. Our findings suggest the existence of two MM molecular subgroups that could benefit from dedicated therapies, such as immune checkpoint inhibitors or targeted therapies, for both human and veterinary medicine.

Abstract

Mucosal melanoma (MM) is a rare, aggressive clinical cancer. Despite recent advances in genetics and treatment, the prognosis of MM remains poor. Canine MM offers a relevant spontaneous and immunocompetent model to decipher the genetic bases and explore treatments for MM. We performed an integrative genomic and transcriptomic analysis of 32 canine MM samples, which identified two molecular subgroups with a different microenvironment and structural variant (SV) content. The overexpression of genes related to the microenvironment and T-cell response was associated with tumors harboring a lower content of SVs, whereas the overexpression of pigmentation-related pathways and oncogenes, such as TERT, was associated with a high SV burden. Using whole-genome sequencing, we showed that focal amplifications characterized complex chromosomal rearrangements targeting oncogenes, such as MDM2 or CDK4, and a recurrently amplified region on canine chromosome 30. We also demonstrated that the genes TRPM7, GABPB1, and SPPL2A, located in this CFA30 region, play a role in cell proliferation, and thus, may be considered as new candidate oncogenes for human MM. Our findings suggest the existence of two MM molecular subgroups that may benefit from dedicated therapies, such as immune checkpoint inhibitors or targeted therapies, for both human and veterinary medicine.

Management of Noncutaneous Melanomas

Noncutaneous melanomas are rare subtypes of melanoma with high rates of metastatic disease and poor overall survival. One-third to one-half of cases are amelanotic, which may contribute to a delay in diagnosis. Immunohistochemistry staining with typical melanoma markers helps confirm the diagnosis. There is no standard staging system across mucosal melanomas. Elective nodal dissection is not recommended and there is a paucity of data to support use of sentinel lymph node biopsy. Mutational analysis should be routinely performed. Systemic therapy options include targeted inhibitors, immunotherapy, and cytotoxic chemotherapy, although further studies are needed to confirm their efficacy.

Adjuvant Therapy and Prognosticators of Survival in Head and Neck Mucosal Melanoma

OBJECTIVES/HYPOTHESIS

To identify prognosticators and determine the efficacies of surgery with adjuvant radiotherapy (SR) and surgery with immunotherapy (SI) of head and neck mucosal melanoma (HNMM).

STUDY DESIGN

Retrospective database study.

METHODS

The 2004 to 2017 National Cancer Database was queried for HNMM patients. Cox proportional hazards and Kaplan-Meier analyses evaluated prognosticators of mortality and survival benefits conferred by SR, SI, or surgery with adjuvant radiotherapy and immunotherapy (SRI). Logistic regression identified predictors of adjuvant radiotherapy or immunotherapy use.

RESULTS

Overall, 1,910 cases (845 surgery, 802 SR, 51 SI, 101 SRI) were analyzed, with 50.3% females and an average age of 68.6 ± 13.8 years. SI was associated with greater overall survival (OS) than surgery (hazard ratio [HR] 0.672; P = .036). SI (HR 0.425; P = .024) and SRI (HR 0.594; P = .045) were associated with superior OS than SR. Older age (HR 1.607; P < .001), female sex (HR 0.757; P = .006), paranasal sinus localization (HR 1.648; P < .001), T4 classification (HR 1.443; P < .001), N1 classification (HR 2.310; P < .001), M1 classification (HR 3.357; P < .001), and positive surgical margins (HR 1.454; P < .001) were survival prognosticators. Adjuvant radiotherapy use was negatively correlated with older age, oral cavity localization, and M0 or T3 tumors (all P < .05). Adjuvant immunotherapy use was positively correlated with younger age and M1 tumors (all P < .05).

CONCLUSIONS

Although SR did not confer survival benefits in HNMM patients, SI and SRI yielded greater OS than surgery alone. SRI was associated with superior survival outcomes than SR. Certain demographic and clinical factors were associated with increased mortality risk. Patient age and certain tumor characteristics were predictors of adjuvant radiotherapy or immunotherapy use.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Clinical outcomes and patterns of failure of head and neck mucosal melanoma treated with multiple treatment modalities

OBJECTIVES

The study aims to analyze the clinical characteristics of head and neck mucosal melanoma (MMHN) and the effects of multiple treatment modalities on distant metastasis, recurrence and survival rates to provide a reference for the individualized treatment of MMHN.

METHODS

We retrospectively reviewed 262 patients with stage III-IVb MMHN treated from March 1986 to November 2018 at our cancer center.

RESULTS

The median follow-up time was 34.0 months (range 1-262 months). The 5-year overall survival (OS), distant metastasis-free survival (DMFS) and disease-free survival (DFS) probabilities were 37.7%, 30.2%, and 20.3%, respectively. The 5-year OS rates for patients with stage III, stage IVA, and stage IVB MMHN were 67.0%, 24.1% and 8.3%, respectively (P < 0.001). A total of 246 (93.9%) patients received surgery, 149 (56.9%) patients received chemotherapy, and 69 (26.3%) patients received immunologic/targeted therapy. A total of 106 (40.5%) patients were treated with radiotherapy: 9 were treated with preoperative radiotherapy, 93 were treated with postoperative radiotherapy, and 4 were treated with radiotherapy alone. In the multivariate Cox regression analysis, primary tumor site, T stage, and immunologic/targeted therapy were independent factors for OS (all P < 0.05). Irradiation technique, T stage, and N stage were independent prognostic factors for DMFS (all P < 0.05). T stage, N stage, and surgery were independent prognostic factors for DFS (all P < 0.05). Distant metastasis was observed in 107 of 262 patients (40.8%), followed by local [74 (28.2%)] and regional [52 (19.8%)] recurrence.

CONCLUSIONS

The main reason for treatment failure in MMHN is distant metastasis. Immunologic/targeted therapy and surgery are recommended to improve the survival of MMHN. The American Joint Committee on Cancer (AJCC) 8th edition staging system for MMHN does stage this disease effectively.

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.

Sequential treatment from mandibulectomy to reconstruction on mandibular oral cancer - Case review I: mandibular ramus and angle lesion of primary intraosseous squamous cell carcinoma

Primary intraosseous squamous cell carcinoma (PIOSCC) is very rare type of squamous cell carcinoma (SCC) that occurs within the jaw and arises from remnants of odontogenic epithelium with no connection to the oral mucosa. This study reports two cases of PIOSCC of the mandible. Reported in this article are two cases of PIOSCC of the mandible that were treated with resection and reconstruction using a fibular free flap. The first case was a 36-year-old male patient who complained of right mandibular pain. Computed tomography (CT) and panoramic radiograph revealed a large radiolucency in the mandibular ramus area. At first, an odontogenic keratocyst was tentatively diagnosed, and an excision procedure was carried out at another clinic. A final biopsy after cyst enucleation revealed well-differentiated SCC, so we proceeded with segmental mandibulectomy and reconstruction using a fibular free flap. The second case was a 48-year-old male patient with left mandibular pain. CT and panoramic radiograph revealed irregular radiolucency in the mandibular angle area near tooth #38. At first, osteomyelitis was tentatively diagnosed, and a curettage was carried out. A later biopsy revealed well-differentiated SCC, so segmental mandibulectomy and reconstruction with a fibular free flap were secondarily performed. Our two cases have had no recurrence. The facial appearance of both patients is satisfactory, and the neo-mandibular body created using a fibular bone transfer displays adequate bony volume.

Review on Canine Oral Melanoma: An Undervalued Authentic Genetic Model of Human Oral Melanoma?

Oral melanoma (OM) is a highly aggressive tumor of the oral cavity in humans and dogs. Here we review the phenotypic similarities between the disease in these 2 species as the basis for the view that canine OM is a good model for the corresponding human disease. Utility of the "canine model" has likely been hindered by a paucity of information about the extent of the molecular genetic similarities between human and canine OMs. Current knowledge of the somatic alterations that underpin human tumorigenesis and metastatic progression is relatively limited, primarily due to the rarity of the disease in humans and consequent lack of opportunity for large-scale molecular analysis. The molecular genetic comparisons between human and canine OMs that have been completed indicate some overlap between the somatic mutation profiles of canine OMs and a subset of human OMs. However, further comparative studies featuring, in particular, larger numbers of human OMs are required to provide substantive evidence that canine OMs share mechanisms of tumorigenesis with at least a subset of human OMs. Future molecular genetic investigations of both human and canine OMs should investigate how primary tumors develop a metastatic gene expression signature and the genetic and epigenetic alterations specific to metastatic sites. Such studies may identify genetic alterations and pathways specific to the metastatic disease which could be targetable by new drugs.

Cutaneous and Mucosal Melanomas of Uncommon Sites: Where Do We Stand Now?

Melanomas arising at uncommon sites include a group of lesions related to unusual localizations in specific ethnic groups. The rarity of the disease often represents a limit to the participation of patients in specific trials. However, this peculiar genetic scenario has important therapeutic implications regarding new oncologic therapies. The aim of this article is to review the clinical features, somatic alterations and therapeutic options for melanomas of uncommon sites. They can be classified as cutaneous and mucosal lesions affecting the nail apparatus, palms/soles, oral mucosa, genital area and scalp. The prognosis may be worse compared to melanomas of other districts, and a prompt diagnosis may dramatically influence the outcome. Dermatologists and oncologists should therefore distinguish this melanoma subgroup in terms of surgical intervention and medical treatment. Due to the lack of mutations in genes usually found in cutaneous melanomas, the discovery of novel targets is required to develop new strategies and to change the prognosis of non-responders or wild-type patients.

A Rare Case of Oral Mucosal Amelanotic Melanoma in a 77-year-old Immunocompromised Man

Primary mucosal melanomas are rare neoplasms that occur in the mouth, esophagus, nasopharynx, larynx, and anogenital mucosa. Mucosal melanomas are rare, accounting for approximately one percent of all melanomas. Of the mucosal melanomas that occur in the head and neck, oral mucosal melanomas compose approximately 25 percent. Here, we present a case of an amelanotic oral mucosal melanoma of the mucosal lip in a 77-year-old male patient with a history of non-Hodgkin's lymphoma and multiple basal and squamous cell carcinomas. The patient presented with a pink, nonpigmented, pedunculated mass on the left superior mucosal lip. Histopathologic examination of the biopsy specimen revealed a diagnosis of a superficial spreading type of malignant melanoma with a nodular component. The patient was referred to a tertiary care center for further management. Multiple risk factors exist for developing melanoma, including immunosuppression. Lymphoproliferative disorders, such as non-Hodgkin's lymphoma, lead to inherent immunosuppression, which can be exacerbated by chemotherapy treatments. Cases of oral mucosal melanoma have a poor prognosis due to delayed diagnosis, anatomic location, and aggressive behavior. Surgical resection is first-line therapy, with regional lymph-node dissection of the neck is recommended in most cases. Radiotherapy and targeted molecular therapy, such as c-KIT inhibitors, can also be used.

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.

Spontaneously occurring melanoma in animals and their relevance to human melanoma

In contrast to other cancer types, melanoma incidence has been increasing over the last 50 years, and while it still represents less than 5% of all cutaneous malignancies, melanoma accounts for the majority of skin cancer deaths, due to its propensity to metastasise. Whilst melanoma most commonly affects the skin, it can also arise in mucosal surfaces, the eye, and the brain. For new therapies to be developed, a better understanding of the genetic landscape, signalling pathways, and tumour-microenvironmental interactions is needed. This is where animal models are of critical importance. The mouse is the foremost used model of human melanoma. Arguably this is due to its plethora of benefits as a laboratory animal; however, it is important to note that unlike humans, melanocytes are not present at the dermal-epidermal junction in mice and mice do not develop melanoma without genetic manipulation. In contrast, there are numerous reports of animals that spontaneously develop melanoma, ranging from sharks and parrots to hippos and monkeys. In addition, several domesticated and laboratory-bred animals spontaneously develop melanoma or UV-induced melanoma, specifically, fish, opossums, pigs, horses, cats, and dogs. In this review, we look at spontaneously occurring animal 'models' of melanoma and discuss their relevance to the different types of melanoma found in humans. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland..

Primary gastric melanoma in adult population: a systematic review of the literature

BACKGROUND

Primary gastric melanoma (PGM) is a rare malignant tumour of the stomach with poor prognosis. The aim of this systematic review was to assess the available literature on this entity and to highlight its biological behaviour and preferred treatment approach.

METHODS

PubMed and Cochrane bibliographical databases were independently searched (last search: 2 February 2020) by two investigators for articles reporting on PGM in the adult population.

RESULTS

Twenty-five studies met the inclusion criteria and concerned collectively 25 patients (18 males and seven females) with an age of 63.4 ± 8.97 years (mean ± standard deviation). Main symptoms included abdominal pain (64%), weight loss (48%) and hematemesis or melena (32%). The most frequent tumour location was the body of the stomach (54.2%). All tumours were surgically resected and the majority of the patients had a partial gastrectomy (52%). Median recurrence time was 5 months and 12% of patients reached 5-year survival landmark.

CONCLUSION

PGM is a rare disease characterized by an aggressive malignant behaviour. Its differential diagnosis from a metastatic lesion is crucial. A prompt diagnosis and therapeutic approach are needed. Further studies are required to elucidate the optimal management of this clinical entity.

Sinonasal amelanotic melanoma with neuroendocrine differentiation: a diagnostic conundrum

Mucosal malignant melanoma of the head and neck (HN) is a rare and aggressive neoplasm which constitutes only 1% of all melanomas. Neuroendocrine differentiation is an extremely unusual phenomenon in mucosal melanomas, of which five cases have been reported. We report a rare case of a 63-year-old female who developed sinonasal amelanotic melanoma with immunohistochemical expression of neuroendocrine markers, presenting a diagnostic dilemma. Ultrastructural evidence of melanosomes and neurosecretory granules aided in arriving at the diagnosis. Aberrant immunoexpression of neuroendocrine markers, particularly in an amelanotic melanoma, has critical diagnostic implications, as various malignancies with undifferentiated histomorphology occur at this site, many of which stain positively with neuroendocrine markers. We discuss the differential diagnoses and recommend a high index of suspicion so as not to miss the diagnosis of mucosal melanoma at this location.

Peritheliomatous pattern: A diagnostic clue for diagnosing metastatic melanoma in cytology

BACKGROUND

A peritheliomatous pattern (PP) in tumors is characterized by a sheath of viable tumor cells closely surrounding a central blood vessel. In the authors' cytology practice, such a PP has been recognized in several metastatic melanoma specimens. The aim of this study was to evaluate the frequency of a PP in cytology samples of melanoma in comparison with other tumors.

METHODS

Eighty archival fine-needle aspiration (FNA) cases of metastatic melanoma were compared with 65 control cases (35 poorly differentiated/metastatic carcinomas, 15 lymphomas, and 15 recurrent/metastatic/high-grade sarcomas). Cytologic findings were correlated with corresponding histologic specimens, which were available for 44 cases (55%) in the melanoma group and for 23 cases (35.38%) in the control group. All slides were examined for a PP and were semiquantitatively graded for comparison.

RESULTS

A PP was present in 51.3% of the cytologic preparations (n = 41) among the melanoma group cases, whereas in the control group, a PP was present in only 3.1% of the cases (n = 2). A PP was present in 65.9% of melanomas with available histologic sections (n = 29) and in 8.7% of tissue samples from the control group (n = 2). A PP was seen more often in cell blocks than direct smear preparations (51.3% vs 40.0%) from patients with melanoma.

CONCLUSIONS

The presence of a characteristic PP can be helpful in diagnosing melanoma in FNA samples because it was present in almost half of the metastatic melanoma cases in this study and was rarely present in other tumor types. A PP is easier to recognize and more often presents in cell blocks than aspirate smears. Ancillary studies such as immunohistochemistry are helpful for excluding other entities that may exhibit a PP.

Sinonasal melanoma: a systematic review of the prognostic factors

The objective was to evaluate the available published data on sinonasal melanoma and analyse its clinical features, treatment modalities, and prognostic factors. An electronic search was undertaken in March 2018 in multiple databases. Eligibility criteria included publications with sufficient clinical, histological, and immunohistochemical information to confirm the diagnosis. Seventy-three publications (439 cases) were included. The lesion was more prevalent in females than in males. There was a higher prevalence in the seventh and eighth decades of life. The lesions mainly presented as epistaxis and commonly involved the nasal cavity. Age (>67.6 years; P=0.0012), primary location (middle turbinate; P=0.0112), disease stage (advanced disease stage; P=0.0026), treatment (radiotherapy; P=0.0111), recurrence (recurrence presented; P=0.0137), and distant metastasis (distant metastasis presented; P=0.0011) were independently associated with a lower survival rate. Recurrence was significantly correlated with age (>67.6 years; P=0.0021), sex (males tended to present a higher recurrence rate than females; P=0.0051), disease stage (stages III and IV presented a higher recurrence rate than stages I and II; P=0.0331), and histological type (amelanotic lesions presented a higher index of recurrence than melanotic lesions; P=0.0095). In conclusion, sinonasal melanoma is a neoplasm with a poor prognosis, presenting a 30.69% possibility of survival after 5 years.

Diffusion Kurtosis Imaging and Intravoxel Incoherent Motion in Differentiating Nasal Malignancies

OBJECTIVES/HYPOTHESIS

To evaluate the usefulness of diffusion kurtosis imaging (DKI) and intravoxel incoherent motion (IVIM) in the differentiation of sinonasal malignant tumors (SNMTs) with different histological types.

STUDY DESIGN

Retrospective observational and diagnostic study.

METHODS

Sixty-five patients with SNMTs who underwent DKI and IVIM were enrolled in this retrospective study, including 27 squamous cell carcinomas (SCCs), 13 olfactory neuroblastomas (ONBs), 14 malignant melanomas (MMs) and 11 lymphomas. The kurtosis (K) and diffusion coefficient (Dk) from DKI and the pure diffusion coefficient (D), pseudodiffusion coefficient (D*), perfusion fraction (f), and the product of D* and f (f∙D*) from IVIM were measured. Kruskal-Wallis and Dunn multiple comparison tests with Bonferroni correction, receiver operating characteristic curve, and logistic regression analyses were used for statistical analysis.

RESULTS

Lymphomas demonstrated the highest K values but lowest Dk, D, D*, f, and f∙D* values among these four malignant tumors. ONBs exhibited high K values and MMs had highest D*, f, and f∙D* values. The cutoff value of ≤0.887 × 10^-3 mm² /sec for f∙D* provided a sensitivity, specificity, and an accuracy of 100%, 98.1%, and 98.5%, respectively, for differentiating lymphomas from the other three entities. The combination of f∙D* and D values showed a sensitivity of 92.9% and a specificity of 92.5% for the discrimination of MMs from ONBs and SCCs. The K value was useful for differentiating ONBs from SCCs, with a threshold value of 0.942 (sensitivity, 84.6%; specificity, 63.0%).

CONCLUSIONS

The combined use of DKI and IVIM is helpful for differentiating among four histological types of SNMTs.

LEVEL OF EVIDENCE

3 Laryngoscope, 2019.

Updated WHO nomenclature of head and neck lesions and associated imaging findings

This article reviews the imaging features of head and neck lesions with updated 2017 World Health Organization (WHO) nomenclature. The major WHO changes include refined terminology of existing entities, descriptions of new tumor types, elimination of defunct categories, and updated biological characterization of various tumor types. In particular, the updates pertaining to the following conditions will be reviewed: tumors of the oral cavity and oropharynx, including HPV-positive or HPV-negative squamous cell carcinoma, small cell carcinoma; tumors of the hypopharynx, larynx, trachea, and parapharyngeal space, including nomenclature revisions for laryngeal neuroendocrine tumors; tumors of the nasal cavity and paranasal sinuses including newly added entities such as NUT carcinoma and biphenotypic sinonasal sarcoma; odontogenic and maxillofacial bone tumors, including the reversal of terminology for certain cystic lesions; tumors of the salivary glands, including updated terminology related to high-grade transformation and polymorphous adenocarcinomas tumors; temporal bone lesions including modifications of the nomenclature and classification criteria; tumor-like lesions of the neck and lymph nodes, with a discussion encompassing developmental cysts, metastases of unknown primary, and heterotopia-associated neoplasia; and mucosal melanoma. Familiarity with the proper WHO terminology for conditions that might be mentioned in differential diagnoses and a general understanding of the behavior of head and neck lesions can help optimize imaging assessment and reporting.

Canine Melanomas as Models for Human Melanomas: Clinical, Histological, and Genetic Comparison

Despite recent genetic advances and numerous ongoing therapeutic trials, malignant melanoma remains fatal, and prognostic factors as well as more efficient treatments are needed. The development of such research strongly depends on the availability of appropriate models recapitulating all the features of human melanoma. The concept of comparative oncology, with the use of spontaneous canine models has recently acquired a unique value as a translational model. Canine malignant melanomas are naturally occurring cancers presenting striking homologies with human melanomas. As for many other cancers, dogs present surprising breed predispositions and higher frequency of certain subtypes per breed. Oral melanomas, which are much more frequent and highly severe in dogs and cutaneous melanomas with severe digital forms or uveal subtypes are subtypes presenting relevant homologies with their human counterparts, thus constituting close models for these human melanoma subtypes. This review addresses how canine and human melanoma subtypes compare based on their epidemiological, clinical, histological, and genetic characteristics, and how comparative oncology approaches can provide insights into rare and poorly characterized melanoma subtypes in humans that are frequent and breed-specific in dogs. We propose canine malignant melanomas as models for rare non-UV-induced human melanomas, especially mucosal melanomas. Naturally affected dogs offer the opportunity to decipher the genetics at both germline and somatic levels and to explore therapeutic options, with the dog entering preclinical trials as human patients, benefiting both dogs and humans.

Oral Melanomas: A Case Series of a Deadly Neoplasm

PURPOSE

To describe and discuss the demographic and clinical features of oral melanomas, which are relatively rare but deadly neoplasms, and list the criteria for their diagnosis to increase early detection.

MATERIALS AND METHODS

An institutional review board-approved retrospective search of oral melanomas was performed in the archives of the University of Florida Oral and Maxillofacial Pathology Biopsy Service (Gainesville, FL) from 2015 through 2018. Exclusion criteria included cases with inconclusive diagnosis, skin involvement, and missing clinical data or slide material. Of 7 patients with a diagnosis of melanoma of the head and neck region, 6 (87.5%) were found to be diagnosed with oral melanomas and met the inclusion criteria.

RESULTS

All 6 patients were at least 45 years (range, 45 to 87 yr). The male-to-female ratio was 4:2. Three patients were asymptomatic and 3 experienced symptoms, including pain, swelling, and tingling. Seven lesions were detected in these 6 patients. Three of these lesions were located on the maxillary gingiva, 2 were on the mandibular gingiva, and 2 involved the palate. Two lesions were diagnosed as spindle cell melanoma, 4 were diagnosed as melanoma, and 1 was diagnosed as a mucosal lentiginous melanoma.

CONCLUSION

Oral melanomas should be considered in the differential diagnosis of oral pigmented lesions, especially on the gingiva or palate, in middle-age and elderly patients. Oral melanomas have a male bias. In addition, supportive criteria enabling early diagnosis of oral melanomas is addressed.

Delayed diagnosis of a primary intraosseous squamous cell carcinoma: A case report

Primary intraosseous squamous cell carcinoma is a rare malignant central jaw tumor derived from odontogenic epithelial remnants. Predominantly, it affects mandible, although both jaw bones may be involved. This report describes a 60-year-old man who was initially misdiagnosed with a periapical infection related to the right lower wisdom tooth. After four months, the patient presented to a private dental clinic with a massive swelling at the right side of the mandible. Panoramic radiographs and advanced imaging revealed a lesion with complete erosion of the right ramus, which extended to the orbital floor. A biopsy from the mandibular angle revealed large pleomorphic atypical squamous cells, which is the primary microscopic feature of a poorly differentiated squamous cell carcinoma.

Evaluation of the expression of Bmi-1 stem cell marker in sinonasal melanomas and its correlation with the expression of cell cycle proteins

Background

Sinonasal melanomas (SNM) are aggressive neoplasms, which present distinct clinicopathological and molecular aspects when compared to cutaneous melanomas (CM). B-cell-specific moloney murine leukemia virus integration site-1 (Bmi-1) is a stem cell marker involved in the regulation of the cell cycle and has been found to be expressed in 70% of CM and 100% of benign nevi. Regarding the cell cycle, Bmi-1 is known to be an upstream repressor of p16, which is a tumor suppressor encoded by the INK4a/Arf locus. Considering this, the aim of this study is to evaluate the immunohistochemical expression of Bmi-1 in a series of SNM and its correlation with the expression of cell cycle proteins (p16 and Ki-67, a nuclear antigen of proliferating cells).

Methods

In 16 cases of SNM, nuclear expression of Bmi-1 and nuclear and cytoplasmic of p16 was classified as: absent, low (> 5 to < 50% of cells) and high (≥50%). Ki-67 proliferation index was represented by the ratio positive cells/ total cells.

Results

Histologically, all cases presented varying amount of necrosis and 75% contained undifferentiated cells. Bmi-1 was detected in 6 cases (37.5%) with high level of expression in 2; p16 expression was seen in 10 cases (62.5%) with high level in 7. The frequency of p16 expression did not differ significantly between tumors with or without Bmi-1 expression. Ki-67 index ranged from 8 to 22%. Neither Bmi-1 nor p16 expression showed correlation with Ki-67 index. Bmi-1 negative tumors presented more extensive necrosis (71.4%); no association between Bmi-1 expression and undifferentiated phenotype was observed.

Conclusions

In our SNM series, low immunohistochemical expression of Bmi-1 was a common phenomenon favoring the hypothesis that mucosal melanoma possibly presents molecular pathways different from the cutaneous counterpart. In SNM, Bmi-1 and p16 expression levels did not correlate with each other or with the cell proliferative index.

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.

Oral malignant melanoma: History of malignant degeneration of a pigmented lesion

Introduction: Oral malignant melanoma (OMM) is a rare malignant lesion of the oral mucosa. It accounts for 0.5% of oral cavity cancers and less than 1% of all melanomas. Most cases arise on the palate or gingiva. OMM is caused by unknown factors. Benign pigmentation may precede the neoplasm by several years. The malignant transformation of benign melanosis is poorly understood. Observation: The aim of this work is to present a new clinical case of oral malignant melanoma which appeared on benign melanosis with a brief review of the literature. A 37-year-old woman presented with a blackish pigmented plaque that covered the hard palate and vestibular maxillary gingiva and a soft, friable 2 cm nodule with ulcerated surface next to the 11, 12 and 13. Fifteen years ago, the patient underwent a biopsy that was in favor of benign melanosis. Unfortunately, the patient was followed for one year and then was lost. Recently, in front of the rapidity of the extension of the lesion, she came again. After biopsy, a final diagnosis of OMM is retained. Commentaries: OMM is often asymptomatic. It presents usually as a 1.5–4 cm, blackish grey, irregular, flat or nodular lesion. The neoplasm can appear on apparently normal oral mucosa and may be preceded by benign pigmented lesions. Few articles discussed malignant transformation of benign melanosis. OMM is characterized by its poor prognosis. The treatment of choice for OMM remains surgery with wide clear margins. Conclusion: Close monitoring is needed to detect signs of transformation and to early diagnose melanoma.

Updates in the management of sinonasal mucosal melanoma

PURPOSE OF REVIEW

Sinonasal mucosal melanoma (SNMM) is an aggressive cancer with a poor prognosis. Although there is significant study surrounding the treatment of sinonasal malignancies and cutaneous melanomas, the rarity of this tumor has largely precluded robust outcomes analyses. The authors of this review seek to provide an overview of the recent literature related to the treatment of SNMM with added context from our institutional experience with this disease.

RECENT FINDINGS

In the surgical management of sinonasal malignancies and SNMM specifically, resection via endoscopic endonasal technique appears to offer comparable oncologic outcomes versus an open approach. The role of adjuvant therapy continues to be debated, but there is strong evidence for improved rates of local control with radiotherapy after complete resection. In the last few years, significant developments have been made in the study of systemic therapies for cutaneous melanoma. The identification of genetic mutations common to mucosal melanoma has allowed for early trials of targeted therapies, but study is ongoing.

SUMMARY

Although the study of SNMM is largely limited to small retrospective case series, treatment continues to evolve. Until effective systemic therapies can be identified, endoscopic resection with adjuvant radiotherapy may offer the best disease-free survival with acceptably low morbidity.

Primary Middle Ear Mucosal Melanoma: Case Report and Comprehensive Literature Review of 21 Cases of Primary Middle Ear and Eustachian Tube Melanoma

OBJECTIVE

To present a case of primary middle ear mucosal melanoma and perform a comprehensive literature review of middle ear and eustachian tube mucosal melanoma.

PATIENT

A 61-year-old female presented with no prior history of melanoma and 3 months of aural fullness. A middle ear mass demonstrated primary mucosal melanoma. The mass extended from mesotympanum into hypotympanum, epitympanum, protympanum, eustachian tube, and mastoid antrum. Additionally, a nonenhancing expansile lesion of the petrous apex was noted on magnetic resonance imaging.

INTERVENTION

Subtotal temporal bone resection with transotic approach to the petrous abnormality was performed. Postoperative adjuvant radiation and immunotherapy were given.

RESULTS

Five months postoperatively, the patient developed an isolated cutaneous metastatic focus treated with wide local excision and has had no further evidence of recurrence to date. Upon comprehensive literature review, patients with primary middle ear melanomas (n = 10) present with otorrhea (50%), aural fullness (40%), and hearing loss (30%) most commonly, while hearing loss (81.8%) and aural fullness (54.5%) were the most common presenting symptoms for eustachian tube melanomas (n = 11). Patients were treated with combinations of surgery, radiation, and/or chemotherapy. Middle ear melanoma demonstrated particularly poor outcomes, with 70% mortality, 20% local recurrence, and 50% distant metastasis, whereas eustachian tube origin demonstrated 9.1%, 18.2%, and 36.4%, respectively.

CONCLUSIONS

Middle ear and eustachian tube mucosal melanomas are exceedingly rare, with middle ear melanomas demonstrating a worse prognosis. Multimodality therapy is commonly used; however, outcomes are poor, with high mortality among affected patients.

[WHO classification of head and neck tumours 2017: Main novelties and update of diagnostic methods]

The publication of the new WHO classification of head and neck tumours in 2017 brought major modifications. Especially, a new chapter is dedicated to the oropharynx, focusing on the description of squamous cell carcinoma induced by the virus Human Papilloma Virus (HPV), and new entities of tumors are described in nasal cavities and sinuses. In this article are presented the novelties and main changes of this new classification, as well as the updates of the diagnostic methods (immunohistochemistry, cytogenetics or molecular biology).