Pleased when surgeon ultimately leaves thyroid? (4)
I believe the answer is:
glad
'pleased' is the definition.
('glad' can be similar in meaning to 'pleased')
I don't understand the rest of the clue.
(Other definitions for glad that I've seen before include "Feeling happy" , "Feeling pleasure" , "More than willing" , "Elated" , "Happy, cheerful" .)