title: [Metanephric adenoma: report of two cases].
abstract: We report 2 cases of metanephric adenoma a rare form of adenoma. One case occurred in a 54-year-old male preoperatively diagnosed with renal cell carcinoma who underwent left partial nephrectomy for a tumor 2 cm in size. Histology revealed a tumor with papillotubular structures consisting of small, uniform tumor cells. In immunohistochemical staining, tumor cells were positive for CD57 and WT-1. Thus, the patient was diagnosed with metanephric adenoma. The other case occurred in a 40-year-old male who underwent left nephroureterectomy for carcinoma of the renal pelvis. Carcinoma of the left renal pelvis was diagnosed as pT3N0M0. Incidental micronodules 2 mm in size and consisting of immature tubular structures were noted in the renal cortex. In immunohistochemical staining, tumor cells were positive for CD57 and WT-1, and the patient was diagnosed with metanephric adenoma. The aforementioned tumors frequently occur in middle-aged women and are often well-defined tumors that project from the renal surface outwards. On angiography, they have a hypovascular pattern and resemble papillary renal carcinoma. Preoperative differentiation of renal cell carcinoma and nephroblastoma is difficult. Mistaking such tumors for malignant tumors and subjecting patients to unnecessary adjuvant therapy must be avoided.
authors.affiliation: Department of Urology, Yokosuka Kyosai Hospital.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Terao
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Susumu
authors.initials: S
authors.lastname: Umemoto
authors.forename: Tatsuaki
authors.initials: T
authors.lastname: Onuki
authors.forename: Kazuki
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohgo
authors.forename: Sumio
authors.initials: S
authors.lastname: Nogcchi
authors.forename: Hiroichi
authors.initials: H
authors.lastname: Kishi
authors.forename: Yukio
authors.initials: Y
authors.lastname: Tsuura
authors.forename: Yoji
authors.initials: Y
authors.lastname: Nagashima
mesh_terms: D000236:Adenoma / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D018959:CD57 Antigens / Q000032:analysis; D003937:Diagnosis, Differential; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D007682:Kidney Pelvis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009392:Nephrectomy; D014057:Tomography, X-Ray Computed; D014513:Ureter / Q000601:surgery; D025721:WT1 Proteins / Q000032:analysis
chemical_list: D014408:Biomarkers, Tumor; D018959:CD57 Antigens; D025721:WT1 Proteins