Clinicopathologic differences in malignant melanoma arising in oral squamous and sinonasal respiratory mucosa of the upper aerodigestive tract.

OBJECTIVE: Primary mucosal melanomas are rare tumors. We compare melanomas arising in 2 histologically different mucosa, the stratified oral squamous mucosa and pseudostratified sinonasal respiratory mucosa, to investigate the clinicopathologic influence of native mucosal histology on the tumor.
METHODS: Clinicopathologic features of 36 melanomas arising in the squamous mucosa of the oral cavity were compared with 59 melanomas arising in the sinonasal respiratory mucosa.
RESULTS: The median age of patients was 61 and 63 years for oral and sinonasal melanomas, respectively, with the squamous and respiratory mucosa covering the maxilla being most frequently involved (68.7% and 66%, respectively). The former had a remarkable male predilection (28 men, 8 women), while the latter affected both sexes equally (29 men, 30 women). The oral melanomas were more likely to be detected in the early in situ or microinvasive stage (4 cases vs none, P =.008) and were more frequently amelanotic (14 vs 12, P =.049) than sinonasal melanomas. The sinonasal melanomas were frequently thicker (median thickness, 9 vs 2.6 mm), polypoid (29 vs none), ulcerated (57 vs 20), and necrotic (57 vs 14) than oral melanoma (P <.001). Pseudopapillary architecture was more frequent in sinonasal melanomas (16 tumors vs none, P <.001), and desmoplastic melanomas were more frequent in the oral mucosa (6 vs 1, P =.005). Sinonasal melanoma showed vascular and deep tissue invasion more frequently than oral melanoma; however, no significant difference in disease-specific survival was noted (median survival, 2.8 years vs 3.0 years; 5-year survival, 37% vs 35%, respectively).
CONCLUSION: Sinonasal melanomas demonstrated aggressive morphologic features significantly more frequently than oral melanomas; however, prognosis remained similar in both groups.