Sinonasal melanoma. A clinicopathologic study of 25 cases and literature meta-analysis

To report on 25 cases of sinonasal melanoma at our institution during 1977 to 1995 and to perform a literature meta-analysis on sinonasal melanoma and study survival statistics.

A retrospective search of pathology and clinical records at our institution to identify patients with sinonasal melanoma; a retrospective search of the English-language literature for cases of documented sinonasal melanoma.

Cases from our institution were included if there was adequate pathologic material confirming the pathologic diagnosis. For the meta-analysis, cases were accepted if they included convincing histologic illustrations or documentation of melanin by Fontana-Masson staining or ultrastructural examination or had an acceptable immunohistochemical profile with some documented clinical follow-up on individual patients.

The following parameters were monitored for patients from our institution: age, sex, possible exposure histories, tumor site, tumor size, type of therapy, clinical outcome, cytochemistry (Fontana-Masson stain), and immunohistochemical profile (S-100, HMB-45, vimentin, cytokeratin). The parameters of the meta-analysis were age, sex, tumor site, and survival data.

Our patient population included 10 men and 15 women aged 23 to 83 years (mean, 65 years). Tumor sites included inferior turbinate, superior nasal cavity, nasal cavity floor/palate, ethmoid sinuses, and maxillary sinus. The immunohistochemical profile was as follows (positive cases): S-100 (14 of .14), HMB-45 (12 of 14), vimentin (9 of 10), cytokeratin (0 of 9). Melanin was demonstrated by Fontana-Masson stain (8 of 8 cases). Follow-up information was available in 25 cases, with follow-up ranging from 1 to 217 months (mean, 39 months). Eleven patients were disease free at 1 to 217 months (mean, 59 months) after excision. Local single recurrences developed in 6 patients at 3 to 84 months (mean, 14 months), and were treated with surgery. Multiple local recurrences were seen in 2 patients. One of them died of disseminated disease, after 2 local recurrences, 60 months after original diagnosis. The other was disease free after 38 months. Ten patients ultimately died of disease within 2 to 60 months after diagnosis (mean, 21 months). Only 2 patients may have developed metastatic disease in the absence of local recurrence. A total of 163 cases were identified from the literature: 53 women, 54 men (56 gender unknown). Stratification by era (pre-1980 vs post-1980) did not reveal any gender differences (pre-1980: 34 women [48%], 37 men [52%]; post-1980: 34 women [55%], 27 men [44%]). However, stratification by era did reveal an age shift toward older patients in the 1980-1995 era. The 5-year median survival for all patients was 36 months. Stratification by era of treatment revealed a long-term survival trend: patients treated before 1980 had somewhat better survival at 60 and 100 months (40% and 36%, respectively) than patients diagnosed and treated between 1980 and 1995 (30% and 23%, respectively), although statistical significance was not reached.

It is unclear why the long-term survival for patients with sinonasal melanoma seems to be decreasing. Despite advances in imaging techniques, which would potentially allow for earlier tumor discovery, and advances in surgical techniques and adjuvant therapeutics, the mean survival for patients with sinonasal melanoma has not improved during the past 15 years.