Abstract
RATIONALE: Post-transplant lymphoproliferative disorder (PTLD) is a well-recognized, but uncommon complication in patients with kidney transplantation, which poses challenges in diagnosis and poor prognosis due to its low incidence and nonspecific clinical manifestations. As a routine follow-up examination method for kidney transplant patients, ultrasound (US) plays a significant role in the diagnosis of PTLD. Therefore, it is critical to evaluate the ultrasonic characteristics of PTLD in transplanted kidney patients for early detection and diagnosis. PATIENT CONCERNS: A 59-year-old female patient was unexpectedly found with a mass in the hilum of the transplanted kidney 12th month after transplantation, which gradually grew up in the following 4 months. The latest US examination found hydronephrosis. Contrast-enhanced ultrasound (CEUS) demonstrated a hypo-enhancement pattern in arterial and parenchymal phases and showed a new irregular area lacking perceivable intensification within the mass, which was considered necrosis. Meanwhile, the patient developed an acute increase in serum creatinine from 122 to 195 μmol/L. DIAGNOSIS: A US-guided biopsy was conducted with the final pathological diagnosis of PTLD (polymorphic). INTERVENTIONS: After receiving 3 times of rituximab and symptomatic treatment, blood creatinine returned to normal but the mass was still progressing in the patient. Therefore, the treatment approach was modified to immune-chemotherapy. OUTCOMES: The patient was in a stable condition to date. LESSONS: PTLD is a rare complication in a transplanted kidney. US and CEUS are the preferred imaging methods in renal transplant patients due to their good repeatability and no nephrotoxicity. This case demonstrates that continuous dynamic monitoring by using US and CEUS has significant value in the detection and diagnosis of PTLD in a transplanted kidney, suggesting early clinical intervention to avoid further progression.