Mucosal Melanoma: Epidemiology, Clinical Features, and Treatment

Malignant melanoma of the conjunctiva metastasizing to the submandibular gland: a case report and review of the literature

BACKGROUND

Conjunctival malignant melanoma is an aggressive tumor with the potential for metastasis and death. It is rare in the black population because of the protective effect of melanin. Metastases are usually to regional lymph nodes, most commonly the preauricular nodes, deep cervical lymph nodes, and the salivary gland.

CASE PRESENTATION

We described the case of a 41-year-old black African woman who presented to our ophthalmology clinic with a painless, right medial pigmented bulbar conjunctival swelling and right preauricular and submandibular swelling. Two years ago, she had similar swelling at the same location in the right eye. She subsequently underwent surgical excision under general anesthesia. Histology of both tissues showed proliferating malignant melanocytes that showed heavy pigmentation disposed of in solid nests, tongues, and sheets obscuring cellular details in these areas. Immunohistochemistry showed tumor cells to stain for HMB45 and Melan A. This led us to conclude that the tumor was a malignant melanoma. The patient died a year after making the diagnosis.

CONCLUSION

Conjunctival melanoma is a rare ocular malignancy that should be considered in cases of pigmented lesions of the eye, especially in people with dark pigmentation. Primary acquired melanosis with atypia or a nevus are known as preexisting melanocytic lesions from which conjunctival melanomas might develop. Metastases are often to preauricular and cervical lymph nodes as well as to the salivary gland. This demonstrates the significance of early presentation, thorough history taking, physical examination, and surgical excision for histopathology.

Carbon-Ion Radiotherapy for Head and Neck Mucosal Melanoma: Preliminary Clinical Outcomes and the MedAustron Approach for Reporting RBE-Weighted Dose With 2 Models

Purpose

Head and neck mucosal melanomas (HNMMs) are aggressive, radiotherapy-resistant cancers. Previous JCROS studies demonstrated improved local control with carbon-ion radiotherapy (CIRT). This study evaluates early outcomes of CIRT for HNMM using the European and Japanese relative biological effectiveness (RBE)-adapted dose prescriptions.

Materials and Methods

Between November 2019 and April 2023, 14 HNMM patients received CIRT treatment. Postoperative CIRT for R2 resection: 9 cases; biopsies only: 5 cases. Immune checkpoint inhibitors used as primary treatment: 6 cases; salvage: 8 cases. CIRT delivered in DRBE dose of 68.8 (64.5-68.8) Gy (RBE)/16 fractions, optimized with the local effect model I (LEM-I, European) for RBE-weighted dose, recalculated using the modified-microdosimetric kinetic model (mMKM, Japanese).

Results

HNMM tumor and nodal stages: cT3: 2 (14%), cT4: 12 (86%), cN1: 1 (7%). The median follow-up was 22 months (range, 4-54). The 2-year local recurrence-free survival, regional recurrence-free survival, overall survival, and distant metastasis-free survival were 100%, 89% (CI, 71-100), 64% (CI, 44-95), and 43% (CI, 22-84), respectively. The median relative volumetric tumor regression at 3, 6, and 12 months post-CIRT was 40%, 63%, and 72%, respectively. CIRT-associated late toxicities were G3 mucositis: 2 (14%) and G3 anosmia: 1 (7%). The immune checkpoint inhibition-related late toxicities were G2 hypophysitis: 1 (11%) and G3 peripheral neuropathy: 1 (11%). The average attainable DRBE coverage for 95% of high-dose clinical target volume was 63.2 ± 6 Gy (RBE) (LEM-I) and 57.4 ± 5 Gy (RBE) (mMKM). The LETd distribution in high-dose clinical target volume was satisfactory, LETd50% (median) = 57.3 ± 6 keV/µm and LETd98% (near minimum) = 46.5 ± 6.1 keV/µm.

Conclusion

Bi-RBE model (LEM-I, mMKM) optimized CIRT protocol improved dose comparability of plans between different systems. It also improved intratumoral LETd distribution and resulted in rapid tumor regression, favorable toxicity profile, and excellent early loco-regional control. It provides a promising alternative to surgery, though distant metastasis remains the key prognostic factor.

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.

Exploring the impact of deubiquitination on melanoma prognosis through single-cell RNA sequencing

Background

Cutaneous melanoma, characterized by the malignant proliferation of melanocytes, exhibits high invasiveness and metastatic potential. Thus, identifying novel prognostic biomarkers and therapeutic targets is essential.

Methods

We utilized single-cell RNA sequencing data (GSE215120) from the Gene Expression Omnibus (GEO) database, preprocessing it with the Seurat package. Dimensionality reduction and clustering were executed through Principal Component Analysis (PCA) and Uniform Manifold Approximation and Projection (UMAP). Cell types were annotated based on known marker genes, and the AUCell algorithm assessed the enrichment of deubiquitination-related genes. Cells were categorized into DUB_high and DUB_low groups based on AUCell scores, followed by differential expression analysis. Importantly, we constructed a robust prognostic model utilizing various genes, which was evaluated in the TCGA cohort and an external validation cohort.

Results

Our prognostic model, developed using Random Survival Forest (RSF) and Ridge Regression methods, demonstrated excellent predictive performance, evidenced by high C-index and AUC values across multiple cohorts. Furthermore, analyses of immune cell infiltration and tumor microenvironment scores revealed significant differences in immune cell distribution and microenvironment characteristics between high-risk and low-risk groups. Functional experiments indicated that TBC1D16 significantly impacts the migration and proliferation of melanoma cells.

Conclusion

This study highlights the critical role of deubiquitination in melanoma and presents a novel prognostic model that effectively stratifies patient risk. The model's strong predictive ability enhances clinical decision-making and provides a framework for future studies on the therapeutic potential of deubiquitination mechanisms in melanoma progression. Further validation and exploration of this model's applicability in clinical settings are warranted.

Rare Head and Neck Cancers and Pathological Diagnosis Challenges: A Comprehensive Literature Review

Head and neck cancers (HNCs) arise from anatomically adjacent sites and subsites, with varying etiological factors, diagnostic strategies, prognoses, and treatment approaches. While conventional squamous cell carcinoma (SCC) is the most common histology in the head and neck district, HNCs encompass a variety of rare histopathological entities, categorized into epithelial tumors such as salivary gland cancers, sinonasal tumors, neuroendocrine tumors, malignant odontogenic tumors, and SCC variants versus non-epithelial tumors including soft tissue sarcomas, mucosal melanomas, and hematological malignancies. Rare HNCs (R-HNCs) represent a diagnostic and clinical challenge, requiring histopathological expertise, the availability of peculiar molecular analysis, and the personalization of local and systemic treatments, all guided by a multidisciplinary tumor board. Here, we provide a comprehensive literature review on R-HNCs, emphasizing key histopathological and molecular characteristics that are crucial for guiding treatment decisions. An insight about the latest developments in systemic treatments is also reported.

An Extremely Rare Case of Primary Malignant Melanoma of the Kidney

Malignant melanoma (MM) is a tumor that usually occurs in the skin, but this malignant tumor can also develop in extracutaneous tissues, including urogenital tissues. In regard to MM occurring in urogenital tissues, bladder origin is common but renal primary MM is extremely rare. In the Department of Emergency and Urology at Gifu Municipal Hospital, a tumor of the right kidney was detected in a computed tomography scan to determine the cause of severe pain in the lower extremities of a 45-year-old Japanese woman. With the clinical diagnosis of renal cell carcinoma, resection of the right kidney was performed under laparoscopy. The cut surface of the tumor encapsulated by a thick fibrous capsule was dark brown, and the tumor cells with large nuclei, large nucleoli, acidophil cytoplasm, and numerous melanin granules showed papillary, solid, or alveolar growth. Immunohistochemically, the tumor cells were positive for Melan A and human melanoma black 45 (HMG45) but negative for transcription factor E3 (TFE3), transcription factor EB (TFEB), cytokeratin 7 (CK7), carbonic anhydrase 9 (CA9), and AEl/AE3. We conducted careful and detailed examinations, including an association of the patient's medical history, but there were no indications for tumors, particularly MM, in any organs. Therefore, she was ultimately diagnosed with primary kidney MM.

Innate Immune Cells in Melanoma: Implications for Immunotherapy

The innate immune system, composed of neutrophils, basophils, eosinophils, myeloid-derived suppressor cells (MDSCs), macrophages, dendritic cells (DCs), mast cells (MCs), and innate lymphoid cells (ILCs), is the first line of defense. Growing evidence demonstrates the crucial role of innate immunity in tumor initiation and progression. Several studies support the idea that innate immunity, through the release of pro- and/or anti-inflammatory cytokines and tumor growth factors, plays a significant role in the pathogenesis, progression, and prognosis of cutaneous malignant melanoma (MM). Cutaneous melanoma is the most common skin cancer, with an incidence that rapidly increased in recent decades. Melanoma is a highly immunogenic tumor, due to its high mutational burden. The metastatic form retains a high mortality. The advent of immunotherapy revolutionized the therapeutic approach to this tumor and significantly ameliorated the patients' clinical outcome. In this review, we will recapitulate the multiple roles of innate immune cells in melanoma and the related implications for immunotherapy.

Establishment of Canine Oral Mucosal Melanoma Cell Lines and Their Xenogeneic Animal Models

Canine oral melanoma is the most prevalent malignant tumor in dogs and has a poor prognosis due to its high aggressiveness and high metastasis and recurrence rates. More research is needed into its treatment and to understand its pathogenic factors. In this study, we isolated a canine oral mucosal melanoma (COMM) cell line designated as COMM6605, which has now been stably passaged for more than 100 generations, with a successful monoclonal assay and a cell multiplication time of 22.2 h. G-banded karyotype analysis of the COMM6605 cell line revealed an abnormal chromosome count ranging from 45 to 74, with the identification of a double-armed chromosome as the characteristic marker chromosome of this cell line. The oral intralingual and dorsal subcutaneous implantation models of BALB/c-nu mice were successfully established; Melan-A (MLANA), S100 beta protein (S100β), PNL2, tyrosinase-related protein 1 (TRP1), and tyrosinase-related protein 2 (TRP2) were stably expressed positively in the canine oral tumor sections, tumor cell lines, and tumor sections of tumor-bearing mice. Sublines COMM6605-Luc-EGFP and COMM6605-Cherry were established through lentiviral transfection, with COMM6605-Luc-EGFP co-expressing firefly luciferase (Luc) and enhanced green fluorescent protein (EGFP) and COMM6605-Cherry expressing the Cherry fluorescent protein gene. The COMM6605-Luc-EGFP fluorescent cell subline was injected via the tail vein and caused lung and lymph node metastasis, as detected by mouse live imaging, which can be used as an animal model to simulate the latter steps of hematogenous spread during tumor metastasis. The canine oral melanoma cell line COMM6605 and two sublines isolated and characterized in this study can offer a valuable model for studying mucosal melanoma.

Endoscopic ultrasound features of rectal melanoma: A case report and review of literature

BACKGROUND

Rectal mucosal melanoma is a rare and highly aggressive disease. Common symptoms include anal pain, an anal mass, or bleeding. As such, the disease is usually detected on rectal examination of patients with other suspected anorectal diseases. However, due to its rarity and nonspecific symptoms, melanoma of the rectal mucosa is easily misdiagnosed.

CASE SUMMARY

This report describes the case of a 58-year-old female patient who presented with a history of blood in her stool for the prior one or two months, without any identifiable cause. During colonoscopy, a bulge of approximately 2.2 cm × 2.0 cm was identified. Subsequently, the patient underwent endoscopic ultrasound (EUS) to characterize the depth of invasion of the lesions. EUS suggested a hypoechoic mucosal mass with involvement of the submucosal layer and heterogeneity of the internal echoes. Following surgical intervention, the excised tissue samples were examined and confirmed to be rectal malignant melanoma. The patient recovered well with no evidence of recurrence during follow-up.

CONCLUSION

This case shows that colonoscopy with EUS and pathological examination can accurately diagnose rare cases of rectal mucosal melanoma.

The influence of viscosity of hydrogels on the spreading and migration of cells in 3D bioprinted skin cancer models

Various in vitro three-dimensional (3D) tissue culture models of human and diseased skin exist. Nevertheless, there is still room for the development and improvement of 3D bioprinted skin cancer models. The need for reproducible bioprinting methods, cell samples, biomaterial inks, and bioinks is becoming increasingly important. The influence of the viscosity of hydrogels on the spreading and migration of most types of cancer cells is well studied. There are however limited studies on the influence of viscosity on the spreading and migration of cells in 3D bioprinted skin cancer models. In this review, we will outline the importance of studying the various types of skin cancers by using 3D cell culture models. We will provide an overview of the advantages and disadvantages of the various 3D bioprinting technologies. We will emphasize how the viscosity of hydrogels relates to the spreading and migration of cancer cells. Lastly, we will give an overview of the specific studies on cell migration and spreading in 3D bioprinted skin cancer models.

[Construction and Validation of Prediction Models of Risk Factors for Early Death in Patients With Metastatic Melanoma]

Objective

To construct nomogram models to predict the risk factors for early death in patients with metastatic melanoma (MM).

Methods

The study covered 2138 cases from the Surveillance, Epidemiology, and End Results Program (SEER) database and all these patients were diagnosed with MM between 2010 and 2015. Logistic regression was performed to identify independent risk factors affecting early death in MM patients. These risk factors were then used to construct nomograms of all-cause early death and cancer-specific early death. The efficacy of the model was assessed with receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA). In addition, external validation of the model was performed with clinicopathologic data of 105 patients diagnosed with MM at Sichuan Cancer Hospital between January 2015 and January 2020.

Results

According to the results of logistic regression, marital status, the primary site, N staging, surgery, chemotherapy, bone metastases, liver metastases, lung metastases, and brain metastases could be defined as independent predictive factors for early death. Based on these factors, 2 nomograms were plotted to predict the risks of all-cause early death and cancer-specific early death, respectively. For the models for all-cause and cancer-specific early death, the areas under the curve (AUCs) for the training group were 0.751 (95% confidence interval [CI]: 0.726-0.776) and 0.740 (95% CI: 0.714-0.765), respectively. The AUCs for the internal validation group were 0.759 (95% CI: 0.722-0.797) and 0.757 (95% CI: 0.718-0.780), respectively, while the AUCs for the external validation group were 0.750 (95% CI: 0.649-0.850) and 0.741 (95% CI: 0.644-0.838), respectively. The calibration curves showed high agreement between the predicted and the observed probabilities. DCA analysis indicated high clinical application value of the models.

Conclusion

The nomogram models demonstrated good performance in predicting early death in MM patients and can be used to help clinical oncologists develop more individualized treatment strategies.

Primary malignant melanoma of the genitourinary tract: case series of a rare form of primary mucosal melanoma

Primary malignant melanoma of the genitourinary tract is extremely rare. We present two such cases in elderly Caucasian females. An 81-year-old female with urinary retention and polypoid urinary bladder mass and a 72-year-old female with gross hematuria and urethral caruncle. After thorough evaluation, they were both eventually diagnosed with primary urogenital melanoma (SOX10 and MART1-positive in tumor cells). In both cases, the presence of melanoma-in-situ and absence of primary melanoma in other sites were consistent with primary urogenital melanoma. Immunotherapy with PD-1 inhibitors and use of neoadjuvant and adjuvant treatment are promising, as treatment guidelines remain unclear and overall survival is low. Additional clinical reporting of primary urogenital melanomas can help in better understanding and ultimately treating it.