In mesial TLE, seizure can begin as early as childhood or even later in adulthood. There is a characteristic remission that can occur during childhood, lasting a few years, but then seizures resume...
The abnormalities most associated with mesial TLE are sclerosis (scarring) of the hippocampus, neuronal cell loss in the hippocampal area, and inappropriate sprouting (growth) of mossy cell fibers.
TLE, as a whole, constitutes a common type of epilepsy. The exact incidence is not clear but it is suspected to make up a significant proportion of medication-resistant epilepsy.
A properly qualified doctor would not misdiagnose in that manner. Medically they are very different conditions, though they can have some similar symptoms. This is why some people can confuse the two.