A male patient age 35 yrs suffering from pain during defecation , burning during defecation and 1st part of stool is hard all for last 7 months. Patient is giving history of once he passed hard stool 7 months back then he devloped all these problems, these problems increasing day by day. Now patient is affraiding of passing stool.

P/R examination finding : severe spasm Proctoscopy : a linear ulcer present at post. anal verge along with a sentinel pile what is the diagnosis and the treatment