A case of presenile dementia with neurofibrillary tangles but without senile plaques in small neurons of the external granular layer of the cerebral cortex

This report describes a case of unclassifiable presenile dementia. A 38-year-old man, blind since shortly after birth, started to exhibit personality changes, such as irritability and withdrawal. The following year he began to experience disorientation, auditory hallucinations, delusions of persecution, memory disturbances, and generalized convulsions. Two years later, the patient exhibited snout reflex, grasp reflex, and small steppage gait. He became apallic and died of acute heart failure at the age of 41, three years after the onset of neurologic symptoms. The neuropathological examination revealed numerous ring-, crescent-, or horseshoe-shaped neurofibrillary tangles around the nuclei of neurons, particularly those in the external granular layer of the cerebral cortex and the dentate gyrus of the hippocampus. However, no senile plaques were found. Neuropil threads and glial cytoplasmic inclusions of the oligodendroglia were detected in the cerebral white matter, hippocampus, basal ganglia, diencephalon, and brainstem. To our knowledge, no similar case of presenile dementia has been described heretofore.