[A case of Hoffmann's syndrome with peripheral neuropathy and various pathological findings in muscle biopsy]

A 58-year-old hypothyroid man developed numbness in the extremities and muscular hypertrophy without pain. Needle electromyography was normal. Nerve conduction study revealed severe entrapment and impaired conduction velocity. Muscle biopsy demonstrated small group atrophy, scattered hypertrophic fibers, interstitial fibrosis and subsarcolemmal vaculoes. These vacuoles were stained dark with NADH-TR. On electron microscopy these vacuoles were filled with aggregated mitochondria and glycogen particles. These myopathological findings have been rarely described in Hoffmann's syndrome or Kocher-Debré-Semelaigne syndrome in the literature. Sural nerve biopsy revealed a loss of myelinated fibers in large diameter and relative increase in small diameter fibers. Teased fiber examination demonstrated segmental demyelination. The nerve biopsy findings indicate slowly progressive axonopathy. In Hoffmann's syndrome, associated peripheral neuropathy may play some role in the manifestation of clinical signs and symptoms including muscle weakness and some sensory disturbance.