Une étiologie exceptionnelle de l’insuffisance rénale aiguë : le lymphome de Burkitt

Renal Infiltration as a Primary Presentation of Burkitt Lymphoma Secondary to Systemic Lupus Erythematosus: A Rarity Unto a Rarity

Burkitt lymphoma (BL) is a highly aggressive non-Hodgkin B-cell lymphoma characterized by the translocation and deregulation of the MYC (MyeloCytomatosis) gene on chromosome 8. Three distinct clinical forms of BL are recognized: endemic (African), sporadic (non-endemic), and immunodeficiency-associated. Bilateral renal infiltration leading to acute kidney injury (AKI) is a rare initial presentation of BL. Diagnosis is usually made after evaluating the histology and immunophenotyping of the affected tissue.

We report a case of a 46-year-old male who presented with symptoms of AKI resulting from infiltrative disease, a primary presentation of lymphoma. The patient was a known case of systemic lupus erythematosus (SLE) for the last five years and was referred to the nephrology department due to acute elevation in creatinine, from 0.8 mg/dL to 3.57 mg/dL. On physical examination, there was no lymphadenopathy. Nephrology and SLE workup revealed low complement protein levels and absolute neutrophils, lymphocytes, and metamyelocytes. Renal ultrasound (USG) showed both kidneys with symmetric and edematous appearance. Biopsy affirmed high-grade B-cell lymphoma, positive for BCL-6 (B-cell leukemia/lymphoma) and CD-10 (cell surface marker) and negative for BCL-2 (B-cell leukemia/lymphoma). PET (positron emission tomography) scan showed extensive hypermetabolic lymphadenopathy in multiple areas. The patient was started on chemotherapy and on continuous renal replacement therapy. He improved clinically, and his creatinine lowered down to 0.8 mg/dL. Repeat USG showed decreased edematous appearance of both kidneys.

Primary renal infiltration by BL is a rare presentation in adults. Prompt renal biopsy will change the course of treatment and can affect the prognosis. It is thoroughly advised to keep this malignancy in mind when making a diagnosis for AKI.

Bilateral primary renal diffuse large B-cell lymphoma: a rare presentation of paediatric renal disease mimicking juvenile nephronophthisis

A 12-year-old boy presented with a prolonged history of headache, fatigue and hypertension. Initial investigations were consistent with presumed non-oliguric end-stage renal disease, leading to a provisional diagnosis of juvenile nephronophthisis. Subsequent imaging demonstrated bilaterally enlarged kidneys without cystic change. Mutation analysis was negative for nephronophthisis, causing diagnostic uncertainty which prompted renal biopsy. Histology revealed a primary renal diffuse large B-cell lymphoma which was highly responsive to chemotherapy, including the anti-CD20 monoclonal agent, rituximab. Renal function improved during lymphoma treatment, with residual chronic kidney disease stage 3a once chemotherapy was completed. Atypical diagnostic features should always prompt re-evaluation of a patient. In this case, the delayed malignancy diagnosis did not have an adverse effect on patient survival or morbidity. The outcome for primary renal lymphoma (PRL) has improved markedly following the introduction of rituximab.