Kidney-localized and temporarily self-limiting CD5-positive intravascular large B-cell lymphoma

A 56-year-old Japanese man patient visited Shimada Municipal Hospital, Shimada, Japan, with complaints of melena, cold sweat, dizziness and anorexia, lasting for three days. Computed tomography (CT) values around the bilateral kidneys and retroperitoneum were increased. Lactate dehydrogenase (LDH) and soluble interleukin-2 receptor (sIL-2R) were elevated in the serum, and the estimated glomerular filtration rate (eGFR) was decreased. Needle biopsy of the kidney indicated CD5-positive intravascular large B-cell lymphoma (IVLBCL) solely involving the capillary lumen. One week after the renal biopsy procedure, LDH, sIL-2R and eGFR levels became improved, and his complaints got relieved even without chemotherapy. Four months later, the patient became febrile and the laboratory markers showed abnormal values again, strongly suggesting the recurrence of IVLBCL. Temporal spontaneous remission of IVLBCL is a rare phenomenon. It is supposed that the renal biopsy might have provoked spontaneous remission via the modulation of the host immune system. (147 words).