Tubulointerstitial capillaries limited intravascular lymphoma of the kidney

Excerpt

A 67-year-old man was admitted in our hospital for intermittent fever and gradually worsening respiratory distress. Pitting edema of the lower legs also appeared 2 weeks before admission. Neither lymphadenopathy nor skin rash was noted on physical examination and computed tomography (CT) scan. Complete blood count showed mild anemia (Hb; 11.5 g/dL) and thrombocytopenia (platelets, 53 × 10³/μL). No atypical cells were seen in peripheral blood. Laboratory data including urinalysis, renal, and liver function tests were normal, but the serum lactate dehydrogenase (LDH, 911 IU/L, normal, 250–450 IU/L) and soluble interleukin 2 receptor (9172 U/mL; normal, 220–450 U/mL) are markedly elevated. Although chest X-P and CT scan were normal, atrial oxygen saturation decreased to 93%. Positron emission tomography (¹⁸F-FDG PET) showed enlargement of both kidneys and intense FDG uptake in the bilateral renal parenchyma (Fig. 1). Random skin biopsy revealed large atypical cell proliferation in capillaries positive for CD20, CD5, and MUM1 and negative for CD3 and CD10 (Fig. 2). A diagnosis of intravascular large B cell lymphoma (IVL) was made. Bone-marrow biopsy also revealed lymphoma invasion. Cytogenetic study on bone-marrow aspirate cells showed normal male karyotype. As bilateral renal parenchyma was intensely FDG avid, we performed kidney biopsy to exclude lymphoma cell invasion. Kidney biopsy revealed a proliferation of large atypical cells with the same phenotype (CD20⁺, CD5⁺, MUM1⁺, CD3⁻, and CD10⁻) as the lymphoma cells in skin biopsy which were confined to peritubular capillary vessels (Fig. 3a, hematoxylin–eosin; b, CD20 and CD34 double immunohistochemical staining). Glomeruli were spared from infiltration of lymphoma cells. The patient was treated with 6 courses of R-CHOP combined with 2 courses of high-dose methotrexate for central nerve prophylaxis and achieved complete remission.

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