No 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).

Although identified as the key environmental driver of common cutaneous melanoma, the role of ultraviolet radiation (UVR)-induced DNA damage in mucosal melanoma is poorly defined. We analyze 10 mucosal melanomas of conjunctival origin by whole genome sequencing and our data shows a predominance of UVR-associated single base substitution signature 7 (SBS7) in the majority of the samples. Our data shows mucosal melanomas with SBS7 dominance have similar genomic patterns to cutaneous melanomas and therefore this subset should not be excluded from treatments currently used for common cutaneous melanoma.

Backgrounds/aimsTo date, this is the largest cohort study on extranodal marginal zone B-cell lymphoma (EMZL) of the ocular adnexa (OA). The aim of the study was to characterise the clinical features of OA-EMZL.MethodsA retrospective multicentre study involving seven international eye cancer centres. Data were collected from 1 January 1980 through 31 December 2017. A total of 689 patients with OA-EMZL were included.ResultsThe median follow-up time was 42 months. The median age was 62 years (range, 8–100 years), and 55 % (378/689 patients) of patients were women. The majority of patients (82%, 558/680 patients) were diagnosed with primary OA-EMZL with Ann Arbor stage IE (90%, 485/541 patients) and American Joint Committee on Cancer stage T2 (61%, 340/557 patients) at the time of diagnosis. The orbit (66%, 452/689 patients) and the conjunctiva (37%, 255/689 patients) were the most frequently involved anatomical structures. The 5-year, 10-year and 20-year disease-specific survival (DSS) were 96%, 91% and 90%, respectively. Stage IE patients treated with external beam radiation therapy (EBRT) as monotherapy (10-year DSS, 95%) were found to have a better DSS than stage IE patients treated with chemotherapy (10-year DSS, 86%). Stage IIIE/IVE patients treated with chemotherapy and rituximab had a better DSS (10-year DSS, 96%) than stage IIIE/IVE patients treated with chemotherapy without rituximab (10-year DSS, 63%).Conclusions and relevanceEMZL is a slow-growing tumour with an excellent long-term survival. Low-dose EBRT as monotherapy should be considered in localised OA-EMZL. Rituximab-based chemotherapy should be chosen in those patients with disseminated disease.