American Urological Association - Renomedullary Interstitial Tumor


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Renomedullary Interstitial Tumor

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  • Small benign tumor composed of renomedullary interstitial cells.
  • Some have suggested that these tumors may have developed as response to hypertension.
  • Almost all are incidental finding, found in up to 40% of adult autopsies.
  • Gross:
    • Small (<5mm), well circumscribed pale gray solid nodules in the medulla (image A).
    • May be multiple or very rarely may form larger mass.
  • Histology:
    • Relatively acellular, with small stellate cells and entrapped renal tubules in a connective tissue matrix (image B).
  • Benign course.