Pediatric primary renal lymphoma presenting with multiple masses: A challenging case report and narrative review.

RATIONALE: Only 20 cases of pediatric primary renal non-Hodgkin's lymphoma have been reported since 1995, rare cases and a variety of imaging manifestations have led to difficulties in its diagnosis and treatment.

PATIENT CONCERNS: Herein, we share in detail a case of primary renal lymphoma (PRL) in a child and summarize the common clinical manifestations, imaging features, and prognostic factors of pediatric PRL by retrospectively analyzing cases reported in the literature. A 2-year-old boy presented to the clinic with a large mass on the right side of his abdomen along with loss of appetite.

DIAGNOSES: Imaging revealed a large right renal mass, nearly replacing the entire renal tissue, along with numerous small nodules in the left kidney. Given no local adenopathy and metastases, the diagnosis was unclear. A percutaneous renal puncture was performed, which proved the diagnosis of Burkitt's lymphoma. Since no bone marrow involvement, this child was diagnosed with pediatric PRL.

INTERVENTIONS: This PRL boy was treated with the NHL-BFM95 protocol and supportive care.

OUTCOMES: Unfortunately, this boy died of multiple organ failure in the fifth month of treatment.

LESSONS: As per literature review, the presentation of pediatric PRL is fatigue, loss of appetite, weight loss, abdominal swelling, or other nonspecific symptoms. Although in 81% of cases it often infiltrates the bilateral kidneys, urine abnormalities caused by pediatric PRL are uncommon. 76.2% of pediatric PRL were boys and 2/3 of all cases presented as diffuse renal enlargement. Those PRL presented as masses could easily be misdiagnosed as WT or other malignancies. Absent of local enlarged lymph node, no necrosis or calcification suggest atypical presentation of renal masses and a percutaneous biopsy is needed in timely establishing the accurate diagnosis for appropriate treatment. Based on our experience, percutaneous renal puncture core biopsy is a safe procedure.