[A case of adult cerebral X-linked adrenoleukodystrophy (X-ALD) accompanying typical hypertrophic neuropathy with marked onion-bulb formation].

We report a case of adult cerebral X-linked adrenoleukodystrophy (X-ALD). His illness started with minimally unsteady gait and slight difficulty in speaking at age 43; then mental deterioration progressed rapidly within two years, which was the characteristic clinical feature of this case. He had not shown any signs and symptoms of spastic paraparesis and adrenal dysfunction. Sural nerve biopsy revealed marked demyelination and moderate loss of nerve fibers, showing typical hypertrophic neuropathy with marked onion-bulb formation, while trilaminar inclusions considered as pathognomonic to X-ALD were not detected in our case. Although onion-bulb formation has sometimes been referred to in the peripheral nerve specimens from X-ALD patients, such a remarkable onion-bulb formation as seen in this case is extremely rare. It suggests that severe destruction of myelin in the peripheral nerve have persisted for a fairly long period without drawing any attention from medical staff.