Replace isset($this->item->extraFields->AAA->value) with
isset($this->item->extraFields->AAA->value) && $this->item->extraFields->AAA->value != ''

This will also check if the value is indeed set but it is empty.

1) You did not include "BBB", should it be placed here... && $this->item->extraFields->BBB->value

2) I received a code error when I tried adding the following to my item template override (of course I replaced AAA & BBB with real alias values)

<?php
Replace isset($this->item->extraFields->AAA->value) with
isset($this->item->extraFields->AAA->value) && $this->item->extraFields->BBB->value != ''
?>

I think you where a bit too literal on this Joe :)
I meant replace as replace in your code, not as in a php function.

This extra check -> && $this->item->extraFields->ALIAS->value != '' checks if the field is set but it has no value.

I think the best option is the shorthand if/ else.
Cleaner and easier to maintain. Trust me on this one, give it a 15 min read and you will understand it better. In 2 - 3 months from now you probably won't be able to remember/ read that single line code.

I know that you are not a developer but since you can understand code I think you should look for the optimal solution.

Thank you for the advice @Krikor :)

Always happy to help Joe :)