<prompt> Commonest type of anal canal carcinoma is?Squamous cell carcinomaAdenocarcinomaAdenoacanthomaPapillary type  <response>: Mainly three types of malignant neoplasm are seen in anal canal Squamous cell carcinoma most common Basal cell carcinoma 2nd most common Melanoma Also remember: Most common type of rectal and colon cancer Adenocarcinoma Ref: S. Das textbook of surgery 3e, Page 1078. 