Excision Tumor 21933

I am looking for coding advise. The physician preformed a excision of a cancerous deep tissue tumor and coded to the best of his ability. We have recieved an insurance denial because it is saying a referral is needed. Can someone please review this note to make sure there are no other codes that could have been used.

left back side, transverse incision made through sub q unitll mass encountered, followed capsule circumferentially, on deep aspect of mass was underedge of trapezius and latissimus, excisied with metz, wound closed with 3-0 vircyl and 4-0 plain gut 6 cm diameter 21933

Excision Tumor 21933