Fungal granulomatous interstitial nephritis presenting as acute kidney injury diagnosed by renal histology including PCR assay
A 73-year-old Japanese man was admitted to the otolaryngology department for the treatment of pharyngeal cancer. Laboratory tests revealed a serum creatinine level of 0.8 mg/dL (71 µmol/L) and an estimated glomerular filtration rate of 72 mL/min/1.73 m2 (1.2 mL/s/1.73 m2) with no abnormality in urinalysis.\nSix courses of a chemotherapy regimen including docetaxel (28 mg/day) and cisplatin (7 mg/day) were given over 5 days, and, concomitantly, a total of 68 Gy of radiation was administered during 2 months. Patient's serum creatinine was 0.9 mg/dL (80 µmol/L) at the end of chemotherapy. One month after the completion of chemotherapy and radiation therapy, the patient's body temperature rose to 40°C. Although chest X-ray showed no consolidation in the lungs, antibiotics (piperacillin sodium and teicoplanin) were started because sputum cultures were found to be positive for Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus. Two days later, the patient was referred to our nephrology department because of elevated serum creatinine and oliguria. Laboratory results were: creatinine, 8.1 mg/dL (716 µmol/L); serum albumin, 2.1 g/dL (21 g/L); and C-reactive protein (CRP), 11.1 mg/dL. The white blood cell count was 14.3 × 103/µL (14.3 × 109/L) with 70% neutrophils. The hemoglobin level was 8.2 g/dL (82 g/L). The serum level of β-d-glucan was high (>600 pg/mL); however, antigen titers for Cryptococcus (the Eiken latex agglutination test; Eiken, Tokyo, Japan), Aspergillus (Platelia ELISA kit; Fujirebio, Tokyo, Japan) and Candida (Platelia ELISA kit; Fujirebio, Tokyo, Japan) were negative.\nUrinalysis showed no proteinuria, 5–9 red blood cells/high-power field and 5–9 white blood cells/high-power field. Abdominal computed tomography (CT) showed markedly enlarged kidneys bilaterally. The central venous line via the internal jugular vein was removed because catheter infection was suspected. Blood and urine cultures were negative; however, culture of the tip of the central venous catheter was positive for C. albicans. Piperacillin and teicoplanin were continued and fluconazole was added for C. albicans. Hemodialysis was started 1 week later, and a biopsy of the patient's left kidney was performed 10 days later after consultation.\nMicroscopic findings showed severe interstitial cell infiltration and fibrosis with granulomatous formation. Inflammatory cells included mononuclear, epithelioid and giant cells. Most of the glomeruli were highly collapsed. Grocott's methenamine silver (GMS) stain showed multiple small, rounded, yeast-like features in the interstitium ().