[Malignant melanoma of soft tissues. Apropos of a case].

A case of malignant melanoma of the quadriceps tendon is reported. This is an uncommon soft tissue sarcoma of melanocytic origin. The appearance on MRI depends on its melanin content. The microscopic appearance is distinctive and prognosis is poor. This tumor should be kept in mind when a nodular lesion is detected in specific tendon or aponeurosis.