According to Hagitt&;s classification, a polyp invading neck in between head and stalk is level:

Haggit&;s Classification for Polyps: Haggit&;s classification for polyps containing cancer according to the depth of invasion By definition, all sessile polyps with invasive carcinoma are level 4 by Haggit criteria Level Depth of invasion by Carcinoma 0 Doesnot invade the muscularis mucosa (Carcinoma-in-situ or Intra mucosal carcinoma) 1 Invades through the muscularis mucosa into the submucosa but is limited to the head of the polyp 2 Invades the level of the neck of the polyp (junction between the head and the stalk) 3 Invades any pa of the stalk 4 Invades into the submucosa of the bowel wall below the stalk of the polyp but above the muscularis propria Ref: Sabiston 20th edition Pgno : 1366