Sequential imaging immediately following intravenous administration of Tc99m pertechnetate (“Meckel scan”) demonstrates an abnormal and persistent focus in the right lower quadrant (RLQ), which begins to appear at the same time as normal mucosal activity in the stomach (arrow).

Differential Diagnosis

•  Ectopic gastric mucosa in a Meckel diverticulum: A persistent focus in the RLQ whose uptake follows that of the mucosa in the stomach is the most likely etiology, given the history.

•  Ectopic gastric mucosa in a duplication cyst: A known potential false-positive, this is less likely, given the typical location of a Meckel diverticulum in the RLQ and the history.

•  Ectopic renal pelvis: Another potential false-positive, this is less likely because the timing of tracer uptake in this lesion follows the stomach, not the urinary system.