Dynamic Tc-99m Sulfur Colloid Lymphoscintigraphy With SPECT/CT Revealing a Postrenal Transplant Lymphatic Leak Mimicking Urinoma.

99mTc sulphur colloid lymphoscintigraphy scan is a safe, noninvasive technique for the visualization of lymphatic pathways in the body. While primarily used to detect lymphatic obstruction, it is also valuable in identifying lymphatic extravasation, guiding targeted treatment strategies. We report a 33-year-old woman who developed a large pelvic fluid collection following renal transplantation, initially misdiagnosed on CT. Dynamic lymphoscintigraphy combined with SPECT/CT accurately identified the etiology and precise anatomic origin of the collection, guiding successful conservative management. This case highlights the complementary role of dynamic lymphoscintigraphy and SPECT/CT in diagnosing unexpected post-transplant complications, where conventional imaging alone may be misleading.