Application of contrast-enhanced ultrasonography in the diagnosis of post-kidney transplant lymphoproliferative disorder in native kidney- a case report.

Background: Post-transplant lymphoproliferative disorders (PTLDs) represent a spectrum of heterogenetic lymphoid proliferations. PTLD is a serious complication that affects the long-term survival of kidney transplant patients. Imaging examination is an important method for detecting and diagnosing PTLD. Contrast-enhanced ultrasonography (CEUS) and CEUS-guided biopsy are important modalities for tumor detection and diagnosis. In this case, we describe a 69 years old man in whom a native kidney PTLD was confirmed by CEUS.

Case Presentation: A 69-year-old male patient who had a kidney transplant 1 year earlier presented with 3 months of progressive myasthenia of both lower limbs associated with amyotrophy and weight loss. Although positron emission tomography/computed tomography (PET-CT) showed a high metabolic lesion in the untransplanted kidney, abdominal contrast enhanced computed tomography cannot detect the lesion in the atrophic left kidney. The above examinations showed that the transplanted kidney was normal. CEUS can detect a homogeneously enhanced lesion in the same location as PET-CT. Subsequently, a biopsy was performed under CEUS guidance, and the final pathological diagnosis was diffuse large B-cell lymphoma. The patient then received the R-CHOP treatment. Unfortunately, pulmonary thromboembolism occurred 2 weeks later, and the patient's condition was not alleviated through active treatment. Finally, the patient's family gave up treatment, and the patient was discharged.

Conclusion: The case suggested that CEUS was a valuable imaging method for patient with renal transplantation to detect and diagnose of PTLD.