The Current Role of Ultrasound in Assessing a Transplant Kidney with Cystic and Solid Lesions
Sarah Tuffy, University College Dublin
Background:
Renal transplantation is the treatment of choice for end-stage renal disease (ESRD). When complications arise, careful image evaluation is pertinent in patient management, and ultrasound (US) plays a key role in this assessment. Ultrasound is the primary modality for imaging transplanted kidneys (TK) as it is widely available and does not use nephrotoxic contrast agents or ionising radiation. This is critical for young patients who require long-term follow-up posttransplant. This case study illustrates the role of US in assessing TK and its use in classifying solid and cystic lesions. US has the ability to accurately characterise simple cysts but has limitations when characterising complex, solid lesions that are suspicious for malignancy. This case underscores the importance of a comprehensive US evaluation of TK when assessing lesions to guide further management.
Case Summary:
A 53-year-old male with a right iliac fossa (RIF) graft from a cadaver donor, performed in 2003, presented acutely with fever, dysuria, and RIF tenderness. Laboratory findings indicated pyelonephritis, prompting an urgent US to assess for hydronephrosis. B-mode US findings revealed a complex solid-cystic lesion. This case presents an unusual scenario where a previously classified and stable Bosniak IIF cyst has evolved into a more complex, solid lesion, appearing sinister in nature. Colour and Power Doppler functions, as well as Superb Microvascular Imaging (SMI), demonstrated subtle internal vascularity, raising concern for malignancy. Given the increased risk of renal cell carcinoma in transplant recipients – typically manifesting in the native kidneys – this transformation solidifies the critical role of US in characterising renal lesions on TK and the importance of a thorough US examination. Contrast-enhanced MRI supported US findings. The lesion was upgraded to Bosniak IV. No overt suspicious adenopathy was identified on MRI. The patient was referred to another site for surgical management.