title: Renal oncocytosis.
abstract: Renal oncocytosis is a rare disorder in which numerous oncocytic nodules develop in the kidney. An additional case is reported here. The patient was a 51-year-old woman who had received hemodialysis for 27 years. Nineteen years previously she had developed a tumorous lesion in the right kidney, which had been diagnosed as oncocytoma with laparotomic biopsy. Recently the kidney was removed because of enlargement of the tumor. The renal parenchyma was entirely replaced with numerous brownish nodules. Histologically, the nodules were composed of nests of uniform oncocytic cells. Ultrastructurally, the oncocytic cells contained numerous mitochondria. Immunohistochemical features of the nodules were identical to those of sporadic oncocytomas, that is, immunophenotypes similar to the distal nephron and reactivity with antimitochondrial antigen. Based on these findings, the lesion was diagnosed as renal oncocytosis. It was not possible to determine whether the larger nodules should be diagnosed as oncocytoma or a part of oncocytosis. Additionally, the germ line mutation of the Birt-Hogg-Dubé (BHD) syndrome gene was examined using the genomic DNA obtained from the peripheral lymphocytes, which failed to show any gene alteration. Despite the rare occurrence pathologists and urologists should be aware of renal oncocytosis, as a precursor lesion of renal oncocytoma and chromophobe renal cell carcinoma.
authors.affiliation: Department of Molecular Pathology, Yokohama City University Graduate School of Medicine, Yokohama, Japan. ynagas@med.yokohama-cu.ac.jp
authors.forename: Yoji
authors.initials: Y
authors.lastname: Nagashima
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Mitsuya
authors.forename: Ko-ich
authors.initials: KI
authors.lastname: Shioi
authors.forename: Sumio
authors.initials: S
authors.lastname: Noguchi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kishida
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hamano
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohgo
authors.forename: Yukio
authors.initials: Y
authors.lastname: Tsuura
authors.forename: Toru
authors.initials: T
authors.lastname: Ogawa
authors.forename: Ichiro
authors.initials: I
authors.lastname: Aoki
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yao
mesh_terms: D018249:Adenoma, Oxyphilic / Q000473:pathology*; D015820:Cadherins / Q000032:analysis; D004252:DNA Mutational Analysis; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053552:Keratin-7; D007633:Keratins / Q000032:analysis; D007668:Kidney / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D007680:Kidney Neoplasms / Q000473:pathology*; D008854:Microscopy, Electron; D008875:Middle Aged; D018396:Mucin-1 / Q000032:analysis; D009378:Neoplasms, Multiple Primary / Q000473:pathology; D011506:Proteins / Q000235:genetics; D011518:Proto-Oncogene Proteins; D025521:Tumor Suppressor Proteins; D014746:Vimentin / Q000032:analysis
chemical_list: D015820:Cadherins; C476078:FLCN protein, human; C507497:KRT7 protein, human; D053552:Keratin-7; D018396:Mucin-1; D011506:Proteins; D011518:Proto-Oncogene Proteins; D025521:Tumor Suppressor Proteins; D014746:Vimentin; D007633:Keratins