[Dropped head plus syndrome; a case report].

We reported a patient with so-called "dropped head plus syndrome", a non-progressive myopathy characterized by striking neck extensor weakness followed by progressive limb weakness which is well controlled by azathioprine. This 74-year-old man complained of neck and shoulder fatigue followed by progressive neck extensor weakness over 7 months. On physical examination, neck extensor strength was 4/5 on the MMT scale, but the remainder of the neurological examination and blood tests were normal. Needle EMG showed myopathic changes in the right trapezius and biceps brachialis muscles. Without any treatment, he developed weakness of upper and lower limb muscles about 8 months later, and Gowers' sign was positive. Blood test and needle EMG was unchanged. Muscle biopsy of the left trapezius, deltoid and supraspinatus muscles disclosed nonspecific myopathic changes consisting of variation in fiber size with disorganized intermyofibrillar networks in all the fibers, and there were rimmed vacuoles in some fibers of the deltoid muscle. There was no change on corticosteroids, but there was a dramatic improvement with azathioprine and his muscle symptoms disappeared. We, therefore, made the diagnosis of "dropped head plus syndrome". This appears to be the first such case in Japan.