Endoscopy 2013; 45(S 02): E110-E111
DOI: 10.1055/s-0032-1326279
Cases and Techniques Library (CTL)
© Georg Thieme Verlag KG Stuttgart · New York

Serrated carcinoma arising from a sessile serrated adenoma

E.-J. Lee
1  Department of Surgery, Daehang Hospital, Seoul, Republic of Korea
M.-J. Kim
2  Department of Pathology, Daehang Hospital, Seoul, Republic of Korea
J. P. Suh
3  Department of Internal Medicine, Daehang Hospital, Seoul, Republic of Korea
S. H. Lee
2  Department of Pathology, Daehang Hospital, Seoul, Republic of Korea
› Author Affiliations
Further Information

Publication History

Publication Date:
11 April 2013 (online)

Sessile serrated adenoma/polyp (SSA/P), a distinct serrated polyp subtype, can progress to colorectal cancer via the serrated neoplasia pathway [1]. On endoscopic examination, SSA/Ps usually show a flat or sessile appearance, a mucus covering, and a type II pit pattern. The endoscopic findings of uncomplicated SSA/Ps are well known; however, the endoscopic features of serrated carcinomas arising from SSA/Ps have not been fully described [2] [3]. Herein, we report a case of serrated carcinoma arising from an SSA/P in a 66-year-old man who underwent endoscopic submucosal dissection (ESD) following colorectal cancer screening.

Colonoscopy revealed a 27-mm laterally spreading tumor in the ascending colon ([Fig. 1]). Most of the mass showed a flat elevated surface with a mucus covering, whereas the peripheral portion displayed a nodular appearance. The central area showed a type II (stellate) pit pattern, whilst the peripheral area displayed a type III (tubular) pit pattern ([Fig. 2]). Because there was a considerable risk of piecemeal resection, the tumor was resected by ESD instead of by endoscopic mucosal resection (EMR) [4].

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Fig. 1 Endoscopic image showing a 27-mm laterally spreading tumor in the ascending colon (arrows) with a mucus-covered surface that has a flat elevated appearance except for the peripheral portion, which displays a nodular surface.
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Fig. 2 Endoscopic appearance after submucosal injection showing a type III (tubular) pit pattern in the nodular area and a type II (stellate) pit pattern in the flat area.

On gross examination, the mass comprised two main parts ([Fig. 3 a]). Histopathological examination of these areas showed that the flat elevated area met the SSA/P criteria (green line), the nodular reddish area corresponded to an intramucosal adenocarcinoma (red line), whilst histologic transition was noted between the two areas (orange line; [Fig. 3 b, c]).

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Fig. 3 Appearances of the resected tumor. a Gross appearance showing a biphasic tumor with a flat elevated area (green line), nodular area (red line), and an intervening transitional area (orange line). b Low power view of the tumor with the three areas indicated by their respective colors on the bar below (original magnification × 12.5). c High power view of each of the tumor areas showing features consistent with an SSA/P in the green area, an intramucosal adenocarcinoma in the red area and an area with low grade dysplasia in the transitional orange area (original magnification × 200).
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Despite increasing attention being paid to SSA/Ps, the endoscopic findings of SSA/Ps that are showing early neoplastic progression are not yet well known. We believe the present case clearly shows a biphasic endoscopic appearance of an SSA/P transitioning to a serrated carcinoma.