Intramural Recurrence Without Mucosal Lesions After an Endoscopic Mucosal Resection for Early Colorectal Cancer
A 58-year-old Korean woman underwent screening colonoscopy in August 2006. Colonoscopic examination revealed a 1.5-cm sessile polyp in the rectum. The polyp was located 9 cm from the anal verge, and a biopsy was performed. Pathological examination suggested the presence of an adenocarcinoma. The patient was referred to our hospital. Her CEA level was 1.5 ng/mL. Abdominal-pelvic CT and rectal magnetic resonance imaging (MRI) showed no evidence of significant focal lesions or distant metastases.\nAn en bloc EMR was performed for the lesion. Histopathologic examination of the specimen showed a moderately-differentiated adenocarcinoma that had invaded the submucosal layer (depth of invasion, 200 µm) with lymphovascular invasion. The surgical margins were negative for cancer cells (length of deep resection margin, 0.4 mm; length of deep resection margin, not clearly reported). At the patient's request, no additional surgical treatment was performed. Routine surveillance was performed for 56 months following the EMR. After 56 months, a routine surveillance PETCT of the abdomen and pelvis revealed a pelvic mass with abnormal hypermetabolism on the left side of the mesorectum. The lesion was highly suspicious for recurrence. Rectal MRI showed a 2-cm solid mass in the left side of the mesorectum with direct invasion into the left midrectal wall at 10 cm above the anal verge. By MRI, the lesion appeared to be a perinodal extension of a lymph-node metastasis.\nColonoscopy revealed a submucosal, tumor-like lesion approximately 2 cm in diameter in the rectum (). The lesion was near the post-EMR scar, 10 cm from the anal verge. The patient underwent radical surgery. Examination of the mucosal surface of the specimen showed a 1.5-cm submucosal mass adjacent to the EMR scar with no evidence of mucosal change. Multiple sections showed a yellowish-tan mass in the submucosal, muscular, and perirectal fat tissues. Pathologic examination of the specimen showed a moderately-differentiated rpT3N1b adenocarcinoma with lymphovascular and perineural invasion. However, no residual cancer was seen at the EMR scar (). The resection margin showed no sign of the adenocarcinoma. The postoperative course was uneventful, and the patient was discharged on the seventh day.