Myotonic dystrophy and lipoma: a new association.

A 58-year-old man developed muscle weakness and had more than 1,000 CTG repeats in the myotonin protein kinase gene. He was diagnosed as having myotonic dystrophy. At the time of diagnosis, a large tumor was detected in his abdominal cavity on CT scan examination. He died from pneumonia 6 years later. At autopsy, the abdominal tumor was diagnosed as a lipoma. Several types of tumor have been reported to be associated with myotonic dystrophy type 1; however, this is the first detailed clinical case demonstrating the possible relationship between myotonic dystrophy and lipoma.