A 74-year-old woman underwent I-131 MIBG imaging to rule out or confirm a l
eft adrenal pheochromocytoma. Significant uptake was seen in the. left side
of the abdomen. Postcontrast coronal MRI revealed that this agent did not
accumulate in the mass but rather in the kidney, The left kidney was compre
ssed by the mass and developed hydronephrosis. Accumulation of I-131 MIBG i
n the left kidney was considered to be due to urinary stasis.