I would love any help if possible finding a code for "Exam under anethesia, rigid proctoscopy, formalin topical rectal treatment and biopsied perianal skin culture. I can't find a code for the formalin topical treatment and I have never heard of it before, not sure if an unlisted code will have to be used.

Here is the procedure note:

The patient was taken to the operating room and placed supine
on the operating room table. After the induction of general anesthesia, the
patient was positioned in lithotomy. On inspection of his perianal skin,
the patient has a severe perianal dermatitis with thickening of the
anoderm, presence of fibrinous exudates, poor anal hygiene and erythema.
Appears to be consistent with fungal perianal infection. The area was
scrubbed and cleaned with removal of his fibrinous exudate and desquamated
skin. A small biopsy was taken in the right lateral position. This was sent
for culture and pathology. There was good hemostasis.

A digital rectal examination was then performed. There were no masses.
There was maroon and bright red blood in the vault. An anal block was
performed with 0.5% Marcaine with epinephrine for a total of 20 mL for pudendal
nerve injection. A rigid proctoscopy was then performed. There was green
stool higher in the vault. There was evidence of radiation proctitis with
extending 8-10 cm proximal to the dentate line with easy friability.
Formalin treatment was then performed; 10% formalin was diluted down to
4-5% using a normal saline dilution. The rigid proctoscopy was not
completely functioning and would not allow for instillation of formalin
without evacuation. The formalin treatment was performed in four quadrants
using a Sawyer anoscopy. It was allowed to remain in contact with the
rectal mucosa for approximately two minutes. On completion, there was
resolution of friability and there was no further bleeding. Rigid
proctoscopy was performed with confirmation of adequate treatment with
formalin. Please note that the perianal skin was attempted to be protected
from exposure to the formalin throughout the procedure.

I apologize for the long question/dictation but any help would be appreciated.