Kidney tumor - cysts, children, adult benign
Benign (usually) adult tumors

Author: Pallav Gupta, M.D. (see Authors page)

Revised: 25 April 2016, last major update March 2016

Copyright: (c) 2003-2016,, Inc.

PubMed Search: Kidney [title] leiomyoma
Cite this page: Leiomyoma. website. Accessed October 26th, 2016.
Definition / General
  • Benign tumor of smooth muscle usually located in the cortex or rarely in the renal capsule (Acta Radiol 2006;47:752)
Essential Features
  • Circumscribed lesion composed of benign spindle shaped smooth muscle cells
  • Found in 4.2% to 5.2% of autopsies
  • Breakpoints in the q13–15 region of chromosome 12 have been seen in leiomyomas and congenital mesoblastic nephroma
  • Tsujimura and colleagues suggested an association between tuberous sclerosis and renal leiomyomas (Urol Int 1996;57:192)
  • Krishnan and colleagues have showed an association between Epstein-Barr virus infection and renal leiomyomas in immunocompromised patients (J Urol 1999 Jan;161:212) )
Clinical Features
  • Usually an incidental finding
  • Most occur in adults; tumors of significant size are more common in young women
Prognosis and Treatment
  • Renal leiomyomas do not have aggressive behavior and do not metastasize
  • The prognosis following surgery is excellent without recurrence
Case Reports
Gross Description
  • White or red peripheral lesion, well defined, with a solid aspect and elastic consistency
Gross Images

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Firm circumscribed tumor

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28 cm tumor

Micro Description
  • Well circumscribed lesion of benign smooth muscle cells
  • Features suggestive of leiomyosarcoma include mitoses, nuclear pleomorphism, necrosis
Micro Images

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Missing Image


Differential Diagnosis
  • Angiomyolipoma: usually vascular and lipomatous components; positive for melanocytic markers