Radiation Nephropathy Complicated by Tubulointerstitial Nephritis with Predominantly Lymphocyte and Plasma Cell Infiltration

A 64-year-old Japanese woman presented with gross hematuria and was diagnosed with stage IVB cervical cancer. Renal dysfunction was observed following chemoradiation therapy, and a renal biopsy revealed renal thrombotic microangiopathy (TMA) and tubulointerstitial nephritis (TIN), which are atypical features of radiation nephropathy. Contrast-enhanced computed tomography revealed wedge-shaped areas of high contrast, consistent with areas of high radiation dose in the kidneys, thus leading to the diagnosis of radiation nephropathy. This case underscores the importance of integrating clinical, pathological, and radiological findings for the diagnosis of radiation nephropathy, atypical renal biopsy findings, and a combination of TIN and renal TMA.