Two cases of frontotemporal dementia with predominant temporal lobe atrophy.

Frontotemporal dementia (FTD) is a subtype of frontotemporal lobar degeneration, which also includes semantic dementia (SD) and progressive non-fluent aphasia. Frontotemporal dementia is characterized by changes in personality and behavioral abnormalities, generally associated with predominant frontal lobe atrophy. Conversely, SD is typically characterized by Gogi (word meaning) aphasia based on semantic memory impairment and is associated with predominant temporal lobe atrophy. However, in the present cases, we diagnosed FTD on the basis of clinical symptoms, such as disinhibition, indifference, and stereotypy, without semantic memory impairment, even though neuroimaging showed predominant temporal lobe atrophy. We suggest that clinical symptoms are the most important cues for an accurate clinical diagnosis and there is no exclusive relationship between the syndrome and atrophy of the temporal lobes.