Primary Melanoma of the Leptomeninges with BAP1 Expression-Loss in the Setting of a Nevus of Ota: A Clinical, Morphological and Genetic Study of 2 Cases

Malignant blue melanoma

Malignant blue melanomas arise from blue nevi and all related intradermal melanocytic proliferations. They harbor specific, mutually exclusive mutations in the G-coupled protein pathway, mainly involving GNAQ or GNA11. Other rare genetic drivers include CYSLTR2 or PCLB4 mutations. PKC and GRM1-gene fusions have been recently added to this list. Malignant blue melanomas have a predilection for the scalp area, presenting as rapidly growing nodules within a pre-existing lesion. Histopathologically, these tumors are located in the dermis and subcutaneous fat and consist of large nodules or expanding dense sheets. Tumor necrosis is commonly seen. Large spindle-shaped and epithelioid melanocytes with high-grade cytologic atypia and frequent mitotic figures are at higher magnification. A benign blue nevus or intermediate-grade blue melanocytoma is frequently found on the side of the central mass. Loss of nuclear BAP1 immunoreactivity is a poor prognostic factor.

Clinicopathological features, current status, and progress of primary central nervous system melanoma diagnosis and treatment

Primary central nervous system (CNS) melanoma is an extremely rare condition, with an incidence rate of 0.01 per 100,000 individuals per year. Despite its rarity, the etiology and pathogenesis of this disease are not yet fully understood. Primary CNS melanoma exhibits highly aggressive biological behavior and presents clinically in a distinct manner from other types of melanomas. It can develop at any age, predominantly affecting the meninges as the primary site, with clinical symptoms varying depending on the neoplasm's location. Due to the lack of specificity in its presentation and the challenging nature of imaging diagnosis, distinguishing primary CNS melanoma from other CNS diseases. The combination of challenges in early detection, heightened tumor aggressiveness, and the obscured location of its origin contribute to an unfavorable prognostic outcome. Furthermore, there has been currently no consensus on a standardized treatment approach for primary CNS melanoma. Despite recent advancements in targeted therapy and immunotherapy for CNS melanoma, patients with primary CNS melanoma have limited treatment options due to their inadequate response to these therapies. Here, we provided a comprehensive summary of the epidemiology, clinical features, molecular pathological manifestations, and available diagnostic and therapeutic approaches of primary CNS melanoma. Additionally, we proposed potential therapeutic strategies for it.

Melanoma in the setting of nevus of Ota: a review for dermatologists

Nevus of Ota, also known as oculodermal melanocytosis or nevus fuscoceruleus ophthalmomaxillaris, is a benign dermal melanocytic nevus that most commonly affects Asian women. While the lesion is largely a cosmetic concern, it has the potential to undergo malignant transformation to melanoma. Patients with nevus of Ota often present to a dermatologist at some point for examination or removal with laser therapy. Therefore, it is important for dermatologists to understand the cutaneous and extracutaneous risks these lesions carry and how they may present to further optimize management and appropriate referrals. This review describes the demographic, clinical, and prognostic features of melanoma in the setting of nevus of Ota, divided by the nature of the primary melanoma: cutaneous, orbital, intracranial.

GNA11 Q209L Mouse Model Reveals RasGRP3 as an Essential Signaling Node in Uveal Melanoma

Uveal melanoma (UM) is characterized by mutually exclusive activating mutations in GNAQ, GNA11, CYSLTR2, and PLCB4, four genes in a linear pathway to activation of PLCβ in almost all tumors and loss of BAP1 in the aggressive subset. We generated mice with melanocyte-specific expression of GNA11^Q209L with and without homozygous Bap1 loss. The GNA11^Q209L mice recapitulated human Gq-associated melanomas, and they developed pigmented neoplastic lesions from melanocytes of the skin and non-cutaneous organs, including the eye and leptomeninges, as well as at atypical sites, including the lymph nodes and lungs. The addition of Bap1 loss increased tumor proliferation and cutaneous melanoma size. Integrative transcriptome analysis of human and murine melanomas identified RasGRP3 to be specifically expressed in GNAQ/GNA11-driven melanomas. In human UM cell lines and murine models, RasGRP3 is specifically required for GNAQ/GNA11-driven Ras activation and tumorigenesis. This implicates RasGRP3 as a critical node and a potential target in UM.

Facial Hyperpigmentation in Skin of Color: Special Considerations and Treatment

Differences in cutaneous diseases in people of color call for nuanced evaluation and management. One of the most common dermatological complaints from patients with skin of color is dyspigmentation, particularly hyperpigmentation. The challenge for clinicians is to establish correct diagnoses along with consistently successful treatments to meet the needs of the increasingly diverse population served. This review focuses on facial hyperpigmentation and outlines the most common skin disorders and treatment options.