Amass in transverse colon

This is what we dissected out from he transeverse colon of a middle aged lady. Entire ascending and transeverse colon was removed, to find only this little pedunculated mass with no features of local involvment or lymph nodes. Did we dissect out too much?

The middle and  ileocolic arteries have to be identified; middle colic artery has to be ligated; the ascending and most of the transverse colon are to be removed

Prepare the ileum for an ileotransverse anastomosis
The dissected specimen with the blackish lump (do you note the appendix poking out at the left?)
The mass within the colon, the walls of which are ...
... cut open
It has a stalk, and the base is surrounded by normal haustrous mucosa of colon
However, the surface is unlike any mucosa