PMC4929366_01
Endoscopic appearance of the appendiceal adenocarcinoma. a A single frond-like villous polyp was present in the rectal lumen and appeared to be located within a diverticulum. b The mucosal pattern appeared distorted, consistent with malignancy.
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F1
A follow-up colonoscopy was then performed 2 months later which noted a single frond-like, villous, broad-based rectal polyp that appeared to be located within a diverticulum (fig. 1a), and which had an area of distorted mucosal pattern consistent with malignancy (fig. 1b).
Preoperative CT scan demonstrating a dilated appendix abutting the right side of the rectal wall.
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F2
A preoperative CT scan demonstrated a dilated appendix with its tip near the rectum which was of unclear significance at that time (fig. 2).
An en bloc resection of the appendix and rectum was performed. The appendix is densely adherent to the rectal wall along the right side and is dilated at its tip.
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F3
En bloc resection of the distal sigmoid colon and proximal rectum together with the appendix was performed (fig. 3).
Anatomic evaluation of the resected specimen. A mass lesion was identified in the tip of the appendix, with direct extension into the lumen of the rectum at the site of the presumed rectal polyp.
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F4
The proximal appendix was normal in appearance (fig. 4).
Histological evaluation of the resected specimen. Direct invasion of the appendiceal adenocarcinoma into the rectal lumen was confirmed histologically.
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F5
Pathology showed adenocarcinoma arising focally within an appendiceal tubulovillous adenoma with direct invasion into the rectum (fig. 5).