Malignant melanoma of soft tissues (clear cell sarcoma) of the foot. Is MRI able to perform a specific diagnosis? Report of one case and review of the radiological literature.

The magnetic resonance (MR) findings in malignant melanoma of soft tissues, also called clear cell sarcoma of tendons and aponeuroses, have been described as a focal abnormality with a specific MR pattern of increased signal intensity (relative to normal muscle) on T1 weighted sequences and variably decreased signal intensity on T2 weighted sequences (relative to surrounding fat). We have reported here a case of malignant melanoma of soft tissues of the foot, studied with ultrasonography (US) and MR, in which MR showed T1-hypointensity, T2-hyperintensity and marked gadolinium uptake. We have described the relationship between the intracytoplasmic melanin amount of and these atypical MR findings.