Mucosal melanomas in the elderly: challenging cases and review of the literature

Podoplanin Drives Amoeboid Invasion in Canine and Human Mucosal Melanoma

Mucosal melanoma metastasizes at an early stage of the disease in human and dog. We revealed that overexpression of podoplanin in tumor invasion fronts (IF) was related to poor prognosis of dogs with mucosal melanoma. Moreover, podoplanin expressed in canine mucosal melanoma cells promotes proliferation and aggressive amoeboid invasion by activating Rho-associated kinase (ROCK)-myosin light chain 2 (MLC2) signaling. PDPN-ROCK-MLC2 signaling plays a role in cell-cycle arrest and cellular senescence escape as a mechanism for regulating proliferation. Podoplanin induces amoeboid invasion in the IFs of mouse xenografted tumor tissues, similar to canine mucosal melanoma clinical samples. We further identified that podoplanin expression was related to poor prognosis of human patients with mucosal melanoma, and human mucosal melanoma with podoplanin-high expression enriched gene signatures related to amoeboid invasion, similar to canine mucosal melanoma. Overall, we propose that podoplanin promotes canine and human mucosal melanoma metastasis by inducing aggressive amoeboid invasion and naturally occurring canine mucosal melanoma can be a novel research model for podoplanin expressing human mucosal melanoma.

IMPLICATIONS

Podoplanin could be a new therapeutic target to restrict the metastatic dissemination of canine and human mucosal melanoma.

Sinonasal mucosal melanoma presenting as a maxillary sinus mass: A case report

Maxillary sinus melanoma is a rare mucosal melanoma difficult to diagnose in the absence of pigmentation. Intranasal masses presenting with the features of occult malignancy and rapid progression should always be investigated in the line of melanoma irrespective of pigmentation. The histopathological and immunohistochemical examination helps to confirm the diagnosis.

Fortuitous discovery of melanomas in the ENT Department - a histopathological and immunohistochemical study

The melanoma, having its origin in the melanocyte cells, is one of the most aggressive forms of skin cancer in the world with one of the highest rates of brain metastasis. The incidence of cutaneous melanoma in the Mediterranean countries varies from three to five cases/100 000 people/year. Its prognosis is based on an early diagnosis. Sinonasal mucosal melanoma (SNMM) is an extremely rare tumor, accounting for 0.3–2% of all melanomas. The non-specific symptomatology is often delaying the presentation of the patient at the hospital and therefore the diagnosis. The SNMM is a highly aggressive tumor, and the presence of metastasis at the diagnosis usually implies a poor prognosis. The management of the melanomas requires a precise pre-therapeutic assessment and a multidisciplinary approach for the diagnosis, with surgical treatment or radiotherapy required in order to ensure a better a quality of life. In this paper, we retrospectively analyzed two cases of mucosal melanoma and one case of cutaneous melanoma of the nose.

PD-L1 expression in malignant melanomas of the skin and gastrointestinal tract

Gastrointestinal melanoma (GM) is a rare but aggressive type of malignant melanoma arising in the gastrointestinal tract. An anti-programmed cell death protein 1 (PD-1) antibody markedly improves prognosis in patients with melanoma. However, little is known regarding the expression of immune-oncology biomarkers in GM compared with skin melanoma (SM), especially in the Asian population. the present study examined clinicopathological characteristics, PD-L1 and HLA expression, and immune-oncology marker expression in 10 cases of GM and 31 cases of SM. Patients with GM exhibited significantly higher incidences of lymph node and distant metastases than patients with SM (P=0.0448 and P=0.0247, respectively). The infiltration of CD8⁺ lymphocytes was significantly higher in GM than in SM (P=0.0231). The infiltration of PD-1⁺ lymphocytes was higher in GM than in SM, but the difference was not significant (P=0.0975). PD-L1-positive melanoma exhibited a higher proportion of BRAF^V600E-positive melanoma than PD-L1-negative melanoma (P=0.0317; 39.4 and 0%, respectively). PD-L1-positive melanoma exhibited significantly higher rates of CD8⁺ and FOXp3⁺ lymphocyte infiltration than PD-L1-negative melanoma (P=0.0221 and P=0.0463, respectively). By contrast, PD-1⁺ lymphocytes did not differ between PD-L1-positive and -negative cases. Furthermore, HLA-positive melanoma exhibited higher proportions of PD-1 (P=0.0101; 53.7 and 15.4%) and CD8 than HLA-negative melanoma (P=0.0818; 66.7 and 38.2%). These results provided useful information regarding tumor immunity in GM and SM and may contribute to the development of treatment strategies for GM.

Prevalence of malignant melanoma in anatomical sites of the oral cavity: A meta-analysis

Oral malignant melanoma (OMM) is a very rare disease entity accounting <1% of all other melanomas. Till date, no comprehensive meta-analysis has been conducted regarding the prevalence of malignant melanoma in the oral cavity. Therefore, the present meta-analysis was conducted to update on the prevalence of malignant melanoma in anatomical sites of the oral cavity. Literature search was performed to congregate reports of last 10 years using databases, such as PubMed and ScienceDirect. The search strings used were "palate," "buccal," "gingiva," "gum," "maxillary," "mandibular," "lip," "tongue," "melanoma," "oral melanoma," "malignant melanoma," "prognosis," "risk factors," "noncutaneous" and "diagnosis" of OMM by combining terms using the Boolean operators. MedCalc 16.4.3 software was used for the analysis. "Random effects model" was used in the analysis due to significant heterogeneity in the studies. Proportion method was used to analyze the prevalence. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed to report the analysis. Out of 130 studies screened, 19 were included in the meta-analysis and a total of 1323 patients were included. The median age of the patients was found to be 61.87 ± 7.78 years (confidence interval 53.8-67 years). All the screened studies showed significant heterogeneity in gender as well as tumor sites (P < 0.0001). Palate (34.29%) was the most commonly affected site in OMM patients. Overall, the results of the meta-analysis suggest that palate is the most prevalent site in OMM. Furthermore, OMM is high in patients between the fifth and sixth decade of life with a male predominance.

[Nasal cavity mucosal melanoma with skin extension mimicking a malignant lentigo with mucosal extension]

Mucosal melanoma is a rare malignant disease developed from melanocyte. We report the case of a patient with nasal cavity mucosal melanoma with a primary clinical and histological diagnosis of malignant lentigo with mucosal spreading. The presence of a c-Kit mutation, in a second lecture and the evolving nature of the lesion, reorientated the diagnosis of malignant lentigo to mucosal melanoma with skin extension. Extensive surgical resection and foramen free flap with costal graft reconstruction may have a local control of the disease. Yet, after one year, a regional evolution involving a parapharyngeal node was treated by stereotaxic radiotherapy. After 5 years, the patient was considered in clinical and radiological remission. Malignant lentigo with mucosal extension is a very rare situation, this diagnoses must be evoqued after setting mucosal melanoma diagnosis.

Betulin silver nanoparticles qualify as efficient antimelanoma agents in in vitro and in vivo studies

The current study was purported to assess the: (i) in vitro toxicity of betulin silver nanoparticles (AgNPs-B), bare and capped with polyethylene glycol (PEG), on two murine melanoma cell lines (B164A5 and B16Ova) and on healthy cell lines (keratinocytes and melanocytes), and (ii) in vivo antitumor efficacy of PEGylated AgNPs-B in an experimental melanoma model. Bare and PEG-capped AgNPs-B were synthesized by a chemical reduction method resulting in stable and non-aggregated spherical AgNPs-B and PEG-AgNPs-B, of narrow size distributions and mean hydrodynamic diameters of 25 nm and 75 nm, respectively. In vitro assessments were achieved by MTT and Annexin V-FITC assays and in vivo evaluation involved non-invasive techniques for the surveillance of the physiological skin parameters changes and histopathological examination of the harvested organs. The in vitro results revealed selective cytotoxicity against melanoma cells, at low doses that are nontoxic to normal cells; higher doses were associated with the loss of selectivity and toxicity for healthy cells. PEGylated formulation of betulin exerted a dose-dependent pro-apoptotic effect, more obvious in the case of B164A5 cells. Histopathological analysis suggested that PEGylated AgNPs-B developed relevant in vivo effects as antimelanoma agents by decreasing the tumor volume and inhibiting the development of secondary tumors.

Clinicopathological characteristics of malignant melanomas of the skin and gastrointestinal tract

The present study examined the differences between gastrointestinal melanoma (GM) and skin melanoma (SM). The clinicopathological characteristics, the expression of melanoma stem cell markers nestin, sex determining region Y-box 2 and ATP-binding cassette sub-family B member 5, and the presence of the BRAF^V600E mutation were evaluated in 10 cases of GM and 31 cases of SM. Patients with GM had an increased mean age compared with those with SM (76 vs. 68 years). In addition, GMs were significantly more likely than SMs to be amelanotic (50 vs. 7%; P=0.001) and display round cells (70 vs. 23%; P=0.02). The mitosis rate was also significantly higher in GM compared with SM (P<0.05). The incidence of lymph-node metastasis (60 vs. 32%; P<0.05) and distant metastasis (10 vs. 6.5%, P=0.02) was significantly higher in GMs compared with SMs. The expression of stem cell markers did not differ significantly between groups, however, in the SM group advanced-stage disease was associated with a significantly higher expression of nestin than early-stage disease (P<0.05). Immunohistochemically, the expression of BRAF^V600E was significantly lower in GMs compared with in SMs (1.0 vs. 3.3; P=0.01). These findings indicate that the identification of these features may aid in the diagnosis of GM and SM, as well as contribute to the development of novel targeted therapies against GM.

Primary mucosal melanoma of the palatine tonsil: Report of a case and review of the literature

BACKGROUND

Mucosal melanoma of the palatine tonsil is extremely rare. Due to its poor prognosis, primary tonsillar melanoma requires prompt recognition and treatment.

METHODS

A 62-year-old female presented with a deeply pigmented and exophytic lesion in the left tonsillar fossa. The patient underwent a partial pharyngectomy through a midline labio-mandibulotomy approach along with a left level I-V neck dissection. Reconstruction with a left radial forearm free flap and a pharyngeal constrictor advancement pharyngoplasty was performed.

RESULTS

The patient remains free of disease at eight months after adjuvant proton therapy and eleven months after surgery. To our knowledge, less than thirty cases have been either reported or referenced in the literature since the early 1900's. This report is the first in English literature to compile all reported cases of primary tonsillar melanoma.

CONCLUSION

Currently, evidence suggests that mucosal melanoma in the palatine tonsil should be treated in the same fashion as other head and neck mucosal melanomas, mindful of the high rates at which locoregional and distant metastases occur.

Standardization of A375 human melanoma models on chicken embryo chorioallantoic membrane and Balb/c nude mice

Cutaneous melanoma is a metastatic disease characterized by high resistance to treatment, the incidence of which has alarmingly increased worldwide over the past years. A thorough characterization of tumor onset, progression and metastasis is compulsory to overcome the gaps existent in melanoma biology. The present study suggests a well-established protocol and a detailed histological description of human melanoma models in ovo and in vivo obtained by the inoculation of A375 cells to chick embryo chorioallantoic membrane (CAM) and Balb/c nude mice. The inoculation of A375 cells on CAM led to the formation of compact primary and secondary tumors on day 4 post-inoculation, with mean surface area values of 2.2±0.4 mm² and 1.5±0.3 mm², respectively. Moreover, the vessels around the tumors presented a spike wheel pattern, indicating a strong angiogenic reaction. All the injected mice, apart from one, developed solid polypoid primary tumors with lobulated surfaces and intense vascularization, and achromic epithelioid malignant melanocytes with vesiculous nuclei and necrosis area were detected. Metastasis was histologically confirmed in only 30% of the mice with the tumor xenografts. These data indicate that the standardization protocols proposed are complex and reproducible, and can be further employed for the therapeutic surveillance of antiangiogenic and anticancer agents.

A Case of Amelanotic Malignant Melanoma of the Maxillary Sinus Presented with Intraoral Extension

Melanoma of the sinonasal cavity has a high incidence of amelanotic presentation. Its diagnosis is difficult for clinicians and pathologists because of its hidden location and lack of pigmentation at the microscopic level. We reported a case of amelanotic melanoma of the maxillary sinus that showed aggressive extension to the oral cavity after extraction of the maxillary tooth. Histologically, the lesion resembled a plasmacytoid tumour. Diagnosis was made through the positive immunohistochemical staining for S100 and HMB-45.