MRI of mucosal malignant melanoma of the head and neck.

PURPOSE: The objective of this study was to determine the characteristic MR findings for mucosal malignant melanomas of the head and neck.

METHOD: We retrospectively analyzed the MR images for six patients with this entity. T1-weighted SE images with and without gadolinium and T2-weighted fast SE images were obtained. MR images were analyzed qualitatively and quantitatively by comparing the signal intensity of the melanoma with that of muscle.

RESULTS: On T1-weighted images, five melanomas were hyperintense and one was isointense. On T2-weighted images, five were of mixed intensity and one showed isointensity. The mean signal intensity ratio of the primary melanoma to muscle was 1.51 and 1.39 on T1-weighted images with and without gadolinium, respectively. These values were not statistically significant.

CONCLUSION: Hyperintensity on T1-weighted images is characteristic of this entity, but not universal.