Ureter Obstructed by Lymphoma Detected on Bone Scan and SPECT/CT: Cutoff sign

Obstructive uropathy occurs due to common causes such as kidney stones, vesicoureteral reflux, posterior urethral valve and urothelial tumors. In addition, there are rare causes such as solid tumors, retroperitoneal fibrosis, primary lymphomas (Non-Hodgkin lymphomas etc.). A 20-year old male with lower back pain underwent a bone scan for differential diagnosis of back pain. The bone scan findings were normal, except for the presence of unilateral renal stasis accompanied by a short segment ureteral stasis. Due to the abrupt termination of the ureteral activity, namely the “cutoff sign”, a subsequent SPECT/CT imaging was focused for differential diagnosis of ureteral stasis. Non-diagnostic CT sections revealed a para-aortic soft tissue mass compressing the ureter. This case underlines the added value of SPECT/CT imaging in subtle scintigraphic findings. The abrupt termination of stasis in the ureter may warrant the application of SPECT/CT in cases with no previous history of urinary tract pathology. SPECT / CT may provide additional benefits of clarifying the etiology.