Low-grade B cell lymphoma in the perirenal space of the left kidney associated with high titer cold agglutinin disease

Abstract

Cold agglutinin disease (CAD) is a subgroup of autoimmune hemolytic anemia caused by monoclonal cold agglutinins produced by clonally expanded B lymphocytes. In primary CAD, lymphoproliferative bone marrow disorder is noted, while as one of the secondary cold agglutinin syndromes (CAS), the initial manifestation of CAD is followed by development of lymphoma. Here, we report a case of low-grade B cell lymphoma developed 3 months after an initial CAD diagnosis. The patient had an extremely high serum cold agglutinin titer (1:16,384) and slightly elevated serum IgM (452 mg/dL; reference, 31-200) with positive monoclonal IgM-kappa chain. After diagnosis of lymphoma-associated CAS, he was managed successfully with six cycles of a BR (bendamustine and rituximab) regimen. Cold agglutinin titers fell rapidly to 1:2048 at 5 months and to 1:512 at 10 months after chemotherapy, and the patient has been in a complete remission for 34 months.

Keywords: Cold agglutinin disease; IgM-kappa; low-grade lymphoma; perirenal lymphoma.

Figure 1

Contrast-enhanced CT image of the abdomen showing a soft tissue mass in the perirenal space of left kidney (A. Coronal view; asterisk). The actual CT-guided biopsy procedure is shown in axial view (B). Biopsied specimen is shown in (C), of which histopathology shows a lymphomatous lesion with lymphocyte aggregates stained with H&E (C. Original magnification; ×200). Scale bar indicates 250 µm.

Figure 2

Lymphoma cells were small to medium-sized (A. H&E stain original magnification ×400), with immunostaining positive for CD20 (B. ×400), and for BCL-2 (C. ×400) while negative for BCL-6 (D. ×400). Immunostaining for Ki-67 was approximately 30% (E. ×400) and positive for smIg-kappa (F. ×400), but negative for smIg-lambda (data not shown). Scale bar indicates 20 µm.