PMC5797806_01
(A) Endoscopic view of the polypoid lesion approximately 15 mm in diameter. (B) Narrow-band imaging did not detect any surface pattern, as it was covered by a white coat. (C) Location of the lesion close to the dentate line.
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F1
Colonoscopy in our hospital revealed an elevated lesion with redness, approximately 15 mm in diameter, extending close to the dentate line (Figure 1). Narrow-band imaging could not detect any surface pattern, as it was covered by a white coat (Figure 1).
Biopsy showed a well-differentiated tubular adenocarcinoma in situ, with fibromuscular obliteration in the lamina propria mucosa.
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F2
Biopsy specimens also indicated adenocarcinoma and fibromuscular obliteration (Figure 2).
Endoscopic ultrasound showing a hypoechoic mass with no invasion of the submucosal layer (arrow).
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F3
Endoscopic ultrasound (EUS) showed a hypoechoic mass in the second layer, while the third and fourth layers were intact (Figure 3).
The resected specimen was cut into 9 pieces for pathology; the red lines were indicative of adenocarcinoma.
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F4
The tumor was removed en bloc, and its margin was free of tumor cells (Figure 4).