It’s wound around swelling (6)
I believe the answer is:
goitre
'swelling' is the definition.
(I've seen this before)
'it's wound around' is the wordplay.
'wound' becomes 'gore' (I've seen this before).
'around' indicates putting letters inside.
'it' inserted within 'gore' is 'GOITRE'.
(Other definitions for goitre that I've seen before include "Enlarged thyroid gland showing as neck swelling" , "Abnormally enlarged thyroid gland" , "Enlarged thyroid gland with swollen neck" .)