Gastrointestinal tattoos.

Tattooing of the gastrointestinal tract is used to facilitate the relocation of biopsy sites or other sites of interest at the time of subsequent biopsy or surgery. Submucosal injection of sterile india ink produces a zone of blue-black coloration that is grossly visible from both the mucosal and serosal surfaces. The pathology of gastrointestinal tattoos has only been briefly mentioned previously in the medical literature. We report two cases of gastrointestinal tattooing: one that was done to mark the margin of resection in a patient with gastric lymphoma, and the second that occurred unintentionally following the administration of activated charcoal for drug overdosage in a patient with undiagnosed active inflammatory bowel disease. Unintentional tattooing of the gastrointestinal tract has, therefore, not been reported.