A Man With Weakness and Swelling in the Neck

A 47-year-old man presented with a 15-year history of progressive proximal muscle weakness in the arms and legs. He also noted thinning of muscle and voluminous swelling of the back of the neck which was progressively worsening. He had some difficulty drinking liquids and a 10-year history of hearing loss.

Family history revealed that his parents had no such symptoms, but two sisters and one brother of a total of nine siblings are similarly affected. Another brother had only muscle weakness and exercise intolerance. The patient had two healthy children.

Laboratory studies including a comprehensive metabolic panel, complete blood count, and thyroid-stimulating hormone were all normal, except a serum creatine kinase test that was mildly elevated at 300 IU/L (normal, <200 IU/L). Serum cortisol and lactate levels were normal.

An EMG done prior to the referral showed normal nerve conduction velocities and small polyphasic motor unit potentials.

A muscle biopsy, done previously and studied with paraffin sections, showed nonspecific findings. A specimen was fixed in glutaraldehyde and was sent to us. The patient refused a second biopsy. Examination revealed mild facial weakness, bilateral sensory neural hearing loss, and thinning of proximal limb muscles, particularly in the arms and thighs. Muscle strength testing revealed neck flexors to be 5−/5; shoulder muscles and pectoralis, 4/5; biceps and triceps, 4+/5; wrist extensors and flexors, 5−/5; hip flexors and extensors, 4/5; quadriceps and iliopsoas, 4+/5; and hamstrings, 5−/5. Distal leg, forearm, and hand muscles were normal, as were reflexes and sensation. He had a prominent posterior neck mass that had the consistency of fat ( Fig. 90-1 ). The examination was otherwise normal.

What is the Differential Diagnosis?

This patient and his family have muscle weakness and prominent fat accumulation in the neck. He also has hearing loss. The condition appeared to be hereditary.

The EMG findings were against spinal muscular atrophy. He could have a limb-girdle dystrophy, but the lack of symptoms in either of his parents and the lack of definite trapezius muscle wasting and scapular winging are against a diagnosis of facioscapulohumeral dystrophy. A metabolic myopathy is a possibility; however, the lack of myotonia on the EMG is against acid maltase deficiency.

The patient’s hearing loss and large lipoma of the neck in family members suggest a multisystem disorder such as mitochondrial myopathy which can manifest with variable phenotypes.