Scintigraphic detection of an occult bleed into a retroperitoneal mass using Tc-99m labeled red blood cells.

A 45-year-old man with chronic lymphocytic leukemia and a retroperitoneal mass underwent Tc-99m labeled red blood cell bleeding imaging to localize a bleeding source. The bleeding scan showed a linear accumulation of radiotracer obliquely oriented along the left upper epigastrium to the right midepigastrium. This area of uptake increased in intensity and assumed a more globular appearance throughout the study, but did not change in location. This is the pattern of a retroperitoneal bleed resulting from active hemorrhage into the retroperitoneal mass.