title: Pulmonary infarcts can mimic pulmonary metastases from renal cancer.
abstract: OBJECTIVE
  Spontaneous regression of pulmonary metastases from renal cell carcinoma is a rare but well documented event. We present 2 recent cases that were radiographically consistent with pulmonary metastases from renal cell carcinoma but were pathologically shown to be pulmonary infarcts with no evidence of metastatic cells. Stable pulmonary infarcts can be misconstrued as metastatic disease in patients with renal cell carcinoma while resolving pulmonary infarcts may represent a subpopulation of patients with apparent spontaneous regression. Clinical implications of these findings are discussed.
  
  
  METHODS
  Clinical and pathological data from 2 patients with large primary renal tumors, venous thrombi and lung masses were reviewed. Data from these cases, as well as pertinent urological and pathological literature, are presented.
  
  
  RESULTS
  Although preoperative assessment was consistent with stage IV renal cell carcinoma, pathological examination of the lung masses in these patients showed no evidence of tumor cells.
  
  
  CONCLUSIONS
  Pulmonary infarcts may mimic resolving or stable pulmonary metastasis in patients with renal cell carcinoma. Accurate clinical staging is crucial for the prognosis and treatment of renal cell carcinoma. Mistaking pulmonary infarcts for metastatic lesions can lead to inaccurate prognoses and inappropriate treatment.
authors.affiliation: Urologic Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Wagner
authors.forename: M J
authors.initials: MJ
authors.lastname: Merino
authors.forename: H I
authors.initials: HI
authors.lastname: Pass
authors.forename: W M
authors.initials: WM
authors.lastname: Linehan
authors.forename: M M
authors.initials: MM
authors.lastname: Walther
mesh_terms: D002292:Carcinoma, Renal Cell / Q000175:diagnosis* / Q000556:secondary*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology*; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D009365:Neoplasm Regression, Spontaneous; D011655:Pulmonary Embolism / Q000175:diagnosis*