Sinonasal and oral malignant melanomas are rare malignancies accounting for less than 2% of all melanomas. Matrix metalloproteinases (MMPs) are proteolytic enzymes required for extracellular matrix degradation in a variety of physiological and pathologic processes including wound healing, embryogenesis, tumor invasion, and metastases. We studied the correlation between expression of MMPs, nucleolar diameter of melanoma cells, different clinical and histologic parameters, and patient's outcome. Seventeen cases of sinonasal and oral malignant melanoma were studied. The expression of MMP2, MMP9, MMP13, and MMP14 was assessed immunohistochemically on paraffinized sections and measured by computer morphometry as well as silver-stained nucleolar diameter. A significant correlation was found between MMP2 and MMP14 expression and patient's outcome. Greater overall survival was seen in patients with average MMP2 expression less than 8000 microm(2)/x20 high-power field (P = .016). In patients with negative MMP14 staining, survival rate by the end of the follow-up was 38% compared with patients with positive MMP14 staining where survival rate was 0 (P = .03). A correlation with age at onset was also found; patients younger than 66 years had better overall survival rates than patients aged 66 years or older (P = .03). The maximal nucleolar diameter (MaxND) was another parameter that significantly correlated with clinical outcome. Patients with MaxND of 8 microm or larger showed a significant worse prognosis compared with the group with MaxND less than 8 microm (P = .0009). Our pilot study demonstrates that MMP2, MMP14, MMP9, and MaxND might be used as prognostic markers in patients with sinonasal and oral malignant melanoma.