Head and neck mucosal malignant melanoma: clinicopathologic correlation with contemporary review of prognostic indicators

Unlike their cutaneous counterparts, head and neck mucosal malignant melanomas (HNMM) behave much more aggressively and their prognostic markers have not been fully elucidated. Therefore, the aim of this study was to review the clinicopathologic features of a contemporary series of primary HNMM, retrieved from archival material of 2 large medical centers, and to explore the association, if any, between these variables, the clinical features, and outcomes. The clinicopathologic, radiographic, and follow-up information as well as the dominant histologic pattern, mitotic rate, presence/absence of pigmentation, necrosis, ulceration, vascular invasion, and host-associated lymphocytic response were retrieved and recorded. Twenty cases were identified including 1 melanoma in situ. Eight-five percent of tumors arose in the sinonasal tract and 3 (15%) in the oral cavity. After a median follow-up of 25 months, all patients with invasive melanoma developed recurrence and/or metastasis. Local recurrences occurred in 82% of the patients after a median of 12 months, and distant metastasis occurred in 71% of the patients after a median of 13 months. Of those with adequate follow-up, 82% died with disease, and the remaining 3 had recurrent or metastatic disease. Fourth-seven percent of tumors were pigmented, 89% showed at least focal necrosis, and 93% demonstrated ulceration. Sixth-eight percent showed vascular invasion and 63% had a brisk host lymphocytic response. Mitotic rates ranged from 2 to 60/10 high-power fields. The absence of an invasive component might be associated with a better prognosis but other clinical and pathological features that predict outcome, and/or could influence therapy, remain to be determined in HNMM.