title: [Mixed epithelial and stromal tumor of kidney].
abstract: OBJECTIVE
  To study the clinicopathological features and differential diagnoses of mixed epithelial and stromal tumor of the kidney.
  
  
  METHODS
  Clinical and pathological characteristics of 4 cases of mixed epithelial and stromal tumor of the kidney were studied.
  
  
  RESULTS
  Three patients were female and one was male. All patients presented with flank pain and hematuria. Radiologic studies revealed cystic and solid masses involving the kidney. Grossly the tumors had a solid and cyst appearance. Microscopically, the tumors were composed of a mixture of stromal and epithelial elements. The epithelial elements were variable in cell types including cuboidal, hobnail and columnar cells. One case showed Müllerian and intestinal epithelial differentiations. Stromal elements essentially consisted of spindle cells, with thick-walled blood vessels and bands of smooth muscle cells as distinctive features of the tumor. Immunohistochemical staining revealed that the epithelial components were positive for AE1/AE3, whereas the stromal components were positive for ER, PR, and SMA. All patients underwent nephrectomy and were well without evidence of recurrence.
  
  
  CONCLUSIONS
  Mixed epithelial and stromal tumor of the kidney is a benign neoplasm with distinct histopathological features. It should be distinguished from many other renal neoplasms. Surgical intervention is a preferred therapy.
authors.affiliation: Department of Pathology, Health Science Center, Peking University, Beijing 100083, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Yang
authors.forename: Xiu
authors.initials: X
authors.lastname: Nie
authors.forename: Jian
authors.initials: J
authors.lastname: Lu
authors.forename: Xiao-yu
authors.initials: XY
authors.lastname: Lu
authors.forename: Yan-yu
authors.initials: YY
authors.lastname: Wei
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.forename: Zhi-hui
authors.initials: ZH
authors.lastname: Han
authors.forename: Zhao-hui
authors.initials: ZH
authors.lastname: Chen
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
mesh_terms: D000199:Actins / Q000378:metabolism; D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007680:Kidney Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009130:Muscle, Smooth / Q000378:metabolism; D018193:Neoplasms, Complex and Mixed / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D009375:Neoplasms, Glandular and Epithelial / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D009392:Nephrectomy / Q000379:methods; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism
chemical_list: D000199:Actins; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone