Mucosal malignant melanoma – a clinical, oncological, pathological and genetic survey

Abstract

Mucosal melanomas constitute 1.3% of all melanomas and they may develop in any mucosal membrane. Conjunctival melanomas (0.5/million/year) and melanomas in the sinonasal cavity (0.5/million/year) are the most common, followed by anorectal melanomas (0.4/million/year) and melanomas in the oral cavity (0.2/million/year). Anorectal melanoma occurs slightly more often in females, whereas oral melanoma has a male predilection. Mucosal melanoma most commonly develops in a patient's sixth or seventh decade of life, and no differences between races have been found except for sinonasal melanoma and conjunctival melanoma, which are very rare in Black people. The symptoms are not tumour-specific and are related to the organ system affected, and the disease is most often diagnosed at an advanced clinical stage. The diagnosis of a primary tumour is difficult, and metastatic cutaneous melanoma and choroidal melanoma must be excluded. Mutations in KIT are frequently found, while BRAF and NRAS mutations are rarely found - except in conjunctival melanomas that carry BRAF mutations. Mutations in the TERT promotor region are also found in mucosal melanomas. Complete surgical resection with free margins is the treatment of choice. The prognosis is poor, with the 5-year survival rate ranging from 0% (gastric melanoma) to 80% (conjunctival melanoma).

Malignant Melanoma Arising in Association with Sinonasal Melanosis: A Case Report and Review of the Literature

“…common followed by the epithelial type [15]. Sinonasal melanomas frequently express S-100 protein, HMB-45 and melan A [15,17]. The melanoma cells in our case were predominately oval to polygonal in shape (epithelioid) and were S-100 protein, HMB-45 and melan A reactive.…”

“…Mucosal melanomas are rare and are reported to have a more aggressive behavior than their cutaneous counterparts [12][13][14][15][16][17]. Sinonasal melanomas appear to be the most common of the head and neck mucosal melanomas [12,18].…”

“…Sinonasal melanomas arise in a variety of sites with approximately 55% arising in the nasal cavity, 12% to 44% in the lateral wall, 8% to 20% in the nasal septum and 10% to 50% in a single sinus [15,19,20]. Melanomas may take a variety of cell shapes with epithelioid, plasmacytoid, undifferentiated, spindle cell, clear cell and mixed types being reported [15,17,21]. The mixed type is most ed cells in the seromucinous glands.…”

“…Unlike cutaneous melanoma, sinonasal melanomas tend to be BRAF mutation negative but show mutations in KIT [16,17,20].…”

“…Sinonasal melanomas are believed to arise from neural crest cells which migrate to the nasal mucosa [17]. Zak and Lawson demonstrated melanocytes within the nasal mucosa, glands and stroma [6].…”