Anorectal and Genital Mucosal Melanoma: Diagnostic Challenges, Current Knowledge and Therapeutic Opportunities of Rare Melanomas

Mucosal melanomas (MM) are rare tumors, being less than 2% of all diagnosed melanomas, comprising a variegated group of malignancies arising from melanocytes in virtually all mucosal epithelia, even if more frequently found in oral and sino-nasal cavities, ano-rectum and female genitalia (vulva and vagina). To date, there is no consensus about the optimal management strategy of MM. Furthermore, the clinical rationale of molecular tumor characterization regarding BRAF, KIT or NRAS, as well as the therapeutic value of immunotherapy, chemotherapy and targeted therapy, has not yet been deeply explored and clearly established in MM. In this overview, focused on anorectal and genital MM as models of rare melanomas deserving of a multidisciplinary approach, we highlight the need of referring these patients to centers with experts in melanoma, anorectal and uro-genital cancers treatments. Taking into account the rarity, the poor outcomes and the lack of effective treatment options for MM, tailored research needs to be promptly promoted.

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

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.

Evolution in Sinonasal Mucosal Melanoma Management

Sinonasal mucosal melanoma is a rare and aggressive cancer with poor prognosis. Surgical resection with clear margins, when possible, remains the treatment of choice. Radiation therapy is generally used in the adjuvant setting with improved rates of local control following complete resection. Traditional chemotherapeutic agents do not improve the rates of locoregional control or survival. Immunotherapy has been used with some responders but with overall relatively poor outcomes. These outcomes highlight the need for new agents and more prospective trials in this space. We provide a unique case report of a patient with an advanced sinonasal mucosal melanoma and an overview of the recent literature pertaining to the management of this disease.

Autoimmune retinopathy with associated anti-retinal antibodies as a potential immune-related adverse event associated with immunotherapy in patients with advanced cutaneous melanoma: case series and systematic review

ObjectiveTo demonstrate the spectrum of autoimmune retinopathy (AIR) associated with immunotherapy for advanced cutaneous melanoma.Methods and analysisRetrospective chart review on patients with advanced cutaneous melanoma who developed AIR after initiating immunotherapy. Complete ophthalmic examination and relevant ancillary testing were performed on each patient. The presence of AIR-associated anti-retinal antibodies was confirmed by western blot and/or immunohistochemical staining. Ophthalmic and systemic outcomes after treatment for AIR were followed over time. A systematic review of AIR associated with immunotherapy for cutaneous or non-ocular mucosal melanoma was carried out in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.ResultsCase 1 developed photopsia and nyctalopia with electroretinographic findings characteristic for melanoma-associated retinopathy 1 week after initiating ipilimumab/nivolumab immunotherapy. Case 2 experienced new severe bilateral visual field loss associated with anti-retinal and anti-optic nerve antibodies while on maintenance nivolumab immunotherapy. Case 3 developed decreased visual acuity due to acute exudative polymorphous vitelliform maculopathy within 2 weeks of initiating ipilimumab/nivolumab immunotherapy. All patients had concurrent extraocular immune-related adverse events in addition to the presence of anti-retinal antibodies on serological testing. 14 published cases of AIR associated with immunotherapy for cutaneous or non-ocular mucosal melanoma were identified and reviewed.ConclusionsImmune checkpoint inhibition can trigger the development of AIR with varied clinical manifestations in patients with advanced cutaneous melanoma. This study highlights the need for close monitoring in cutaneous melanoma patients receiving immunotherapy who develop new visual symptoms with or without funduscopic changes, as well as the potential role for screening of patients prior to initiating immunotherapy.

Molecular Profiling and Novel Therapeutic Strategies for Mucosal Melanoma: A Comprehensive Review

Mucosal melanoma is a rare and aggressive subtype of melanoma. Unlike its cutaneous counterpart, mucosal melanoma has only gained limited benefit from novel treatment approaches due to the lack of actionable driver mutations and poor response to immunotherapy. Over the last years, whole-genome and exome sequencing techniques have led to increased knowledge on the molecular landscape of mucosal melanoma. Molecular studies have underlined noteworthy findings with potential therapeutic implications, including the presence of KIT mutations, which are potential targets of tyrosine kinase inhibitors currently in use in the clinic (imatinib), but also SF3B1 mutation, CDK4 amplifications, and CDKN2A gene deletions, which are presently under investigation in clinical trials. Recent results from a pooled analysis of patients with mucosal melanoma treated with immunotherapy have suggested that the combination of immune checkpoint inhibitors might improve survival outcomes in this subset of patients, as compared with single-agent immunotherapy. However, these results are not confirmed across different studies, and combo-immunotherapy correlates with a higher rate of adverse events. In this review, we describe the clinical, biological, and genetic features of mucosal melanoma. We also provide an update on the results of approved systemic treatment in this setting and overview the therapeutic strategies currently under investigation in clinical trials.

Report of a recurrent tongue malignant melanoma and review of literature

Primary oral mucosal melanoma is a rare disease. Etiopathogenesis of oral mucosal melanoma (OMM) is inadequately understood. The prognosis of OMM is very poor . Due to its low incidence and late recognition, the optimal treatment modality is not well established. Surgery with free margins is the mainstay of treatment.