title: An unusual form of crystal-forming chronic interstitial nephritis following long-term exposure to tosufloxacin tosilate.
abstract: Fluoroquinolones are known to cause acute renal failure because of interstitial nephritis with or without epithelioid granulomas. We report the first case of slowly progressive renal failure caused by crystal-forming chronic interstitial nephritis with non-Langerhans' cell histiocytosis after long-term exposure to a fluoroquinolone, tosufloxacin tosilate. Lesions consisted of spindle- to cuboidal-shaped histiocytes with minimal collagenous matrix and low-level lymphocyte infiltration replacing normal tubulointerstitial structure of the kidney. Histiocytes were positive for CD68, but negative for S-100, suggesting they were derived from macrophages. There were numerous rhomboid- to needle-shaped crystal deposits in the cytoplasm of histiocytes, which showed bright birefringence under polarized light. No immunoglobulin deposits were seen in the kidney, and no evidence of paraproteinemia/lymphoproliferative diseases was identified in this patient. Despite a negative drug lymphocyte-stimulating test result using tosufloxacin tosilate, withdrawal of the drug and treatment with steroids gradually improved renal function. In this report, we describe the clinical course and histopathologic findings of this patient and discuss the possible pathogenesis.
authors.affiliation: Department of Nephrology, Saitama Medical College, Saitama, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Okada
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Shuhei
authors.initials: S
authors.lastname: Kotaki
authors.forename: Naofumi
authors.initials: N
authors.lastname: Ikeda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takane
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Kanno
authors.forename: Souichi
authors.initials: S
authors.lastname: Sugahara
authors.forename: Shinichi
authors.initials: S
authors.lastname: Ban
authors.forename: Makoto
authors.initials: M
authors.lastname: Nagata
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Suzuki
mesh_terms: D058186:Acute Kidney Injury / Q000209:etiology; D002908:Chronic Disease; D024841:Fluoroquinolones / Q000009:adverse effects* / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D009287:Naphthyridines / Q000009:adverse effects* / Q000627:therapeutic use; D009395:Nephritis, Interstitial / Q000139:chemically induced* / Q000150:complications / Q000473:pathology*; D013995:Time
chemical_list: D024841:Fluoroquinolones; D009287:Naphthyridines; C055185:tosufloxacin