Outcome of sinonasal melanoma: clinical experience and review of the literature.

BACKGROUND: Primary sinonasal malignant melanoma (SNMM) is a rare clinical entity. There is neither a classification nor a staging system nor an evidence-based treatment concept established. Our objective was to find potential risk factors predicting the outcome.
METHODS: Twenty-five patients with histologically confirmed SNMM were consecutively included and retrospectively analyzed. Staging methods were nasal endoscopy, CT, MRI, and positron emission tomography (PET) scan. Patients were selected for a curative or palliative concept. All patients had postoperative follow-up with control-MRI at 3 and 6 months. Restaging was performed when local recurrence occurred.
RESULTS: Nineteen patients underwent primary surgery with curative intention; in 16 cases with tumor free margins. Thirteen patients (68%) had transnasal endoscopic surgery, 4 lateral rhinotomy, and 2 transfacial approach with orbital exenteration. Six patients (32%) had palliative therapy and 7 patients (37%) had adjuvant radiotherapy. Despite radical operations, 6 patients (37%) showed local recurrence and 8 patients (50%) developed distant metastasis. In 2 patients with incomplete surgery, regional metastasis was noted. The median disease-free interval was 18 months, and the median overall survival rate was 23 months.
CONCLUSION: SNMMs of the ethmoid and maxillary sinuses have a worse prognosis than other localizations in the nasal cavity; infiltration into the skull base, orbit, or facial soft tissue correlates with a very poor outcome corresponding to the palliative situations. Furthermore, local recurrence insinuates aggressive disease with short survival rate. A main difference from its cutaneous counterpart seems to be a primary tendency to hematogenic spread. Further research is needed to confirm these findings.