[Dystrophia myotonica type 1 associated with diffuse astrocytoma showing gliomatosis cerebri-like imaging finding: a case report].

The patient was a 43-year-old woman. She had been aware of progressive muscle weakness since around the age of 30. Two months ago, she began to have difficulty making sense of conversation. She was transported to our hospital after choking, and upon arrival, she was found to have generalized muscle weakness and myotonia, along with disorientation. A brain MRI revealed widespread high-intensity lesions in the cerebral white matter on FLAIR images, findings similar to gliomatosis cerebri (GC). Genetical analysis revealed a diagnosis of dystrophia myotonica type 1 (DM1). A brain biopsy revealed a diffuse astrocytoma. There have been no previous reports of DM1 associated with diffuse astrocytoma and imaging findings similar to GC, and we report this patient together with a literature review.