The most common and most likely answer to this crossword clue is the 8 letter word GANGLION
I've seen this crossword clue in Independent
G
A
N
G
L
I
O
N
More clues leading to the result GANGLION
- Band hero a bundle of nerves
- Courageous person follows criminal group into nerve centre
- Pack animal has problem with tendon
- Group meeting brave man with a swelling
- Hero of group in nerve centre
- Mob hero is bundle of nerves
- Nerve centre workers needing person of courage
- Group chased by big cat becoming a bundle of nerves
- Going after criminals, hero is a bundle of nerves
- Courageous person getting behind band — that shows a bit of nerve
Buddy explains!

The straight part
We know that "problem with /ten/don" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case problem with /ten/don = ganglion.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does GANGLION mean?
GANGLION noun- An encapsulated collection of nerve-cell bodies, located outside the brain and spinal cord.
- Any of certain masses of gray matter in the brain, as the basal ganglia.
- (by extension) A centre of intellectual or industrial force, activity, etc.
- A cystic tumour on a tendon sheath or joint capsule; a ganglion cyst.