RÉSUMÉ
We report a very rare case of Hoffmann's syndrome with muscle hypertrophy complicating hypothyroidism. A 24-year-old man presented with a 2-year history of forgetfulness, swelling in his face, shoulder and calf, and motor weakness in his lower extremities. His calf and shoulder muscles were hypertrophic. Neurological examination revealed hoarseness of the voice, proximal muscle weakness, reduced deep tendon reflexes and a mildly ataxic gait. Laboratory tests indicated markedly elevated serum muscle enzymes and lipids, a high thyroid-stimulating hormone level and low free triiodothyronine and free thyroxine levels. Electromyographic evaluation showed myopathy. Oral L-thyroxine treatment was started and at a 1-month follow-up examination, mental status and physical performance were improved. This report shows that in the differential diagnosis of myopathy with pseudohypertrophy, Hoffmann's syndrome should be considered