The most common and most likely answer to this crossword clue is the 7 letter word POLYPUS
I've seen this crossword clue in The Guardian
P
O
L
Y
P
U
S
More clues leading to the result POLYPUS
Buddy explains!

The straight part
We know that "Growth" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case growth = polypus.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 POLYPUS mean?
POLYPUS noun- A cardiac thrombus usually found post-mortem.
- An octopus.