Case Presentation: A 66-year-old African-American female with past medical history of hypertension, anemia, atrial flutter, and chronic kidney disease presented at OSH with pneumonia complicated by encephalopathy. Initial labs were notable for Na 123 mmol/L, BUN 15 mg/dL, Cr 2.1 mg/dL, WBC 15.6, Hgb 8.4 g/dL. The patient had a long and complicated hospital course. She required renal replacement therapy with continuous veno-venous hemodialysis and intermittent hemodialysis. A left kidney biopsy showed minimal interstitial fibrosis with 10% tubular atrophy and heavy infiltration of the renal cortex by undifferentiated neoplastic cells, mostly within the peritubular capillaries. These cells stained positive for CD45, PAX5, CD79a, and BCL6, and negative for CD34. The extent of spread was difficult to evaluate because other biopsy sites were negative for IVLBCL along with bone marrow biopsy, CSF, and bronchoalveolar lavage. The patient received 8 days of modified R-CEOP with cytarabine, etoposide, cyclophosphamide, and steroids followed by a second round of R-CEOP for 13 days. Patient was transferred to the ICU three times due to multi-organ failure and septic shock, requiring intubation. In the ICU, the patient was eventually transitioned to comfort care measures and ultimately expired prior to terminal extubation.
Discussion: Intravascular large B-cell lymphoma (IVLBCL) is classified by the World Health Organization as a rare extranodal large B-cell lymphoma. It is characterized by growth of lymphoma cells within vessel lumina, particularly capillaries. There are two variants – Western, commonly involving the skin, CNS, and most solid organs, and Asian, commonly presenting with hematophagocytic syndrome and bone marrow involvement. Due to its ability to affect any organ system and produce nonspecific constellations of symptoms, IVLBCL is often difficult to diagnose. Symptoms are typically related to the organ systems involved. In cases with infiltration of the kidney, most patients present with AKI marked by increasing BUN and Cr. Diagnosis is dependent on tissue sampling. In our patient, neoplastic cells had invaded peritubular capillaries. Renal involvement in lymphoma is common, however IVLBCL presenting with purely renal involvement has only been reported in 14 patients. IVLBCL has a high mortality rate, with one study reporting median survival of 3 months in 6 untreated patients, complicated by disease rarity and difficulty making the diagnosis. Treatment is typically chemotherapy involving anthracycline with data supporting the addition of rituximab for better outcomes.
Conclusions: IVLBCL is a rare disease with myriad clinical presentations. We present a case with pure renal involvement, a particularly rare manifestation. Early treatment is key to survival, highlighting the need to consider IVLBCL in the differential diagnosis of AKI.