Intramural Recurrence Without Mucosal Lesions After an Endoscopic Mucosal Resection for Early Colorectal Cancer
A 54-year-old Korean man underwent screening colonoscopy in May 2007. The colonoscopic examination revealed a 1.5-cm sessile polyp in the rectosigmoid colon. The polyp was located 20 cm from the anal verge. An en bloc EMR was performed for this lesion. Histopathologic examination of the specimen showed a moderately-differentiated adenocarcinoma invading the submucosal layer (depth of invasion, 750 µm). There was no definite lymphovascular invasion, and the surgical margins were negative for cancer cells (length of deep resection margin, 0.7 mm; length of deep resection margin, not clearly reported). The patient was referred to Severance Hospital, but additional surgical treatment was not performed.\nDuring the 43 months after the EMR, routine surveillance was performed. After the 43 months, the patient's carcinoembryonic antigen (CEA) level was elevated (5.10 ng/mL). Examinations to exclude the possibility of recurrent rectosigmoid colon cancer, including computed tomography (CT) from the abdomen to the pelvis and 18-fluorodeoxy-glucose-positron emission tomography (FDG-PET), demonstrated local recurrent sigmoid colon cancer without distant metastasis. A colonoscopy showed an EMR scar without gross evidence of mucosal local recurrence ().\nThe patient underwent radical surgery. Examination of the mucosal surface of the specimen showed no specific lesion. Examination of the serosal surface revealed a firm, solid, mass-like lesion (7 cm × 3 cm) that was 10 cm from the proximal resection margin and 4 cm from the distal resection margin. Multiple sections showed a yellowish-tan mass located in the submucosal, muscular, and subserosal areas. Pathologic examination of the specimen showed a moderately-differentiated rpT4aN0 adenocarcinoma with lymphovascular and perineural invasion (). The postoperative course was uneventful and the patient was discharged on the tenth day.