An unusual case of polyp with multiple appears honeycomb-like depressions.

The patient is a 63-year-old woman. She underwent lower gastrointestinal endoscopy at her local doctor, and a serrated lesion with a honeycomb-like depression in the surface mucosa of the ascending colon measuring 35 mm in size was observed. The lesion was thought to be a sessile serrated lesion (SSL), but since there was a lot of mucus and it was difficult to observe the inside of the depression, SSL with dysplasia was also mentioned as a possible diagnosis. The patient was referred to our department and underwent endoscopic submucosal dissection of the colon. The pathological results showed no dysplasia component, and the diagnosis of SSL with inverted growth was made. Inverted SSL has been reported in the past, but a lesion with a honeycomb-like depression has never been reported before, making this an interesting lesion. We report here the mechanism of the depression and the morphology of the depression, together with a review of the literature.