Neuronal ceroid lipofuscinosis diagnosed via skin biopsy.

We aim to report that skin biopsy, a non-invasive test by neurological standards, may lead to a diagnosis. A 4-year-old male presented with a 2-year history of epilepsy and progressive developmental regression. The patient had a mildly elevated ammonia level; however, evaluation for the accumulation of excess serum amino acids and evaluation of urine for organic acids was negative. MRI revealed cerebral atrophy, and an electroencephalogram demonstrated multifocal sharp and slow waves. Due to the progressive degenerative neurologic presentation, a neurologic storage disease was favored. An axillary skin biopsy was performed, revealing eosinophilic intra-cytoplasmic inclusions within the eccrine glands. A periodic acid-Schiff stain also highlighted these inclusions. Electron microscopic studies demonstrated characteristic multiple membrane-bound inclusions within the eccrine epithelial cells, containing curvilinear inclusion material characteristic of neuronal ceroid lipofuscinosis. The clinical, histological, electron microscopic and enzymatic studies were diagnostic of late-infantile onset neuronal ceroid lipofuscinosis.