title: Small renal oncocytoma with central cystic degeneration.
abstract: A case of a small renal oncocytoma with central cystic degeneration, 15 mm in diameter, is reported. Contrast-enhanced computed tomography showed the tumor contained a central hypoattenuating region and had an irregular, heterogeneously enhanced wall. Magnetic resonance images showed a well-circumscribed lesion and the T(1)-weighted image indicated medium signal intensity, whereas the T(2)-weighted image indicated slight hypointensity. Both T(1)- and T(2)-weighted images showed central hyperintensity. Our preoperative diagnosis was renal cell carcinoma originating in a renal cyst wall or cystic renal cell carcinoma. Nephrectomy was performed because frozen-section examination did not completely rule out malignancy. The final pathological diagnosis of the entire surgical specimen was renal oncocytoma with cystic degeneration. To our knowledge, this is the 14th case of renal oncocytoma with central cystic degeneration reported in the published works. We discuss herein the variant forms of oncocytoma and difficulties with their preoperative diagnosis, especially when the tumor is small.
authors.affiliation: Department of Urology, Publish Central Hospital of Matto Ishikawa, Matto, Ishikawa, Japan. kokodama@aol.com
authors.forename: Koichi
authors.initials: K
authors.lastname: Kodama
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Nagano
authors.forename: Manabu
authors.initials: M
authors.lastname: Akimoto
authors.forename: Shioto
authors.initials: S
authors.lastname: Suzuki
mesh_terms: D018249:Adenoma, Oxyphilic / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D000368:Aged; D001707:Biopsy, Needle; D002292:Carcinoma, Renal Cell / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D003937:Diagnosis, Differential; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D052177:Kidney Diseases, Cystic / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009367:Neoplasm Staging; D009392:Nephrectomy / Q000379:methods; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome