Colonic abscess induced by India ink tattooing.

Endoscopic tattooing with India ink is generally regarded as a safe procedure that enables ready identification of endoluminal cancer from the serosal surface. However, significant complications have been reported, including local inflammatory pseudotumor formation, peritonitis, rectus muscle abscess, small bowel infarction, and phlegmonous gastritis. Although the mechanism of complication is not completely understood, it may be related to the chemical compounds contained in the ink solution and enteric or extraenteric bacterial inoculation by injection needle or the ink itself. Authors encountered a case of a 60-year-old man with a resectable sigmoid colon cancer which was tattooed with India ink for subsequent localization in the intraoperative setting. During the laparoscopic operation, the proximal and distal margin of the lesion appeared edematous with bluish color. The distal resection margin was extended approximately 5 cm more than expected because of long extent of edematous mucosa. Histologic examination of the edematous tattooing area revealed an ink abscess spreading laterally above the muscularis propria. Although tattooing is widely used and relatively safe, the presented case indicates the risk of infection or inflammation by tattooing.