Scintigraphic patterns of lymphocele in post-renal transplant

Lymphocele is a common cause of fluid collection in post-renal transplant patients. Most of these patients are routinely followed up with ^99mTc diethylenetriaminepentaacetate renal dynamic scintigraphy. The present study retrospectively reviews the range of findings with renal dynamic scintigraphy in documented lymphoceles. A lymphocele was diagnosed when there was a pelvic collection on ultrasonography with a similar biochemical composition to plasma. Four types of scintigraphy patterns were noted in lymphocele in a total of 13 patients. In nine patients there was an initial photopenic area, which progressively filled up with tracer activity equal to that of the background level in delayed images. In two other patients, the activity in the initial photopenic area exceeded the background activity in delayed images. A persistently photopenic area was seen in early and delayed images in the two remaining patients. In addition, a rim of increased tracer activity was noted surrounding the photopenic area in four patients in the early images. In conclusion, an initial photopenic area (with or without a surrounding rim of increased tracer activity), which fills up with tracer in delayed images seems to be the most common pattern seen in lymphoceles in scintigraphic studies of renal transplants. The presence of a rim sign may add confidence to the reporting of a collection as a lymphocele.