[Case of peritubular capillary dominant intravascular large B-cell lymphoma (PTC dominant IVLBCL) successfully treated with chemotherapy].

A 72-year-old woman developed common cold-like symptoms, diarrhea, a staggering gait, and persistent anorexia from the beginning of May 2009. In the middle of May, her general fatigue worsened, and she was transported to our hospital by ambulance. Abdominal CT showed bilateral renal enlargement, and her general condition and renal function rapidly deteriorated. The soluble interleukin-2 receptor (sIL-2R) level was elevated to 5,928 U/mL, and gallium scintigraphy showed a weak uptake in both kidneys. We considered the possibility of malignant lymphoma, and performed a renal biopsy, which showed no glomerular abnormalities, but disclosed the accumulation of large, atypical lymphoid cells with a high N/C ratio and dark chromatin in peritubular capillaries (PTC). On immunohistochemical staining, these atypical cells were found to be CD5(+), CD20 (+/-), CD10(-), CD3(-), and CD7(-), leading to a diagnosis of intravascular large B-cell lymphoma (IVLBCL). Since gallium scintigraphy showed no uptake in other organs, and examination of the cerebrospinal fluid and bone marrow revealed no tumor cells, the patient was considered to have kidney-limited IVLBCL. Chemotherapy was started immediately, which resulted in an improved general condition. Although her renal function deteriorated sufficiently to require dialysis, she was weaned from dialysis. After treatment with chemotherapy, the enlarged kidneys returned to the normal size. Subsequently, she has been receiving chemotherapy intermittently, and has remained free of recurrence. In general, IVLBCL mainly involving the kidney is difficult to diagnose antemortem, and is sometimes found at autopsy. We suggest that bilateral renal enlargement with renal failure of unknown origin should raise the suspicion of malignant lymphoma requiring a prompt renal biopsy. Cases of LBCL in which lymphoma cells fill PTC, as in this patient, have rarely been reported. We believe that this case is extremely valuable in understanding the pathogenesis of intravascular lymphoma invading the kidney; therefore, we report it with a review of the literature.