Kidney nontumor

Developmental & cystic diseases

Simple cysts

Topic Completed: 1 November 2011

Minor changes: 1 October 2019

Copyright: 2003-2019,, Inc.

PubMed Search: Simple cysts [title] kidney

Mandolin S. Ziadie, M.D.
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Cite this page: Ziadie MS. Simple cysts. website. Accessed November 29th, 2021.
Definition / general
  • Occasional finding that increases with age (0.1% in children, 20% at age 50+ years) and may present as a mass lesion
Clinical features
  • 65% of renal masses, may be confused with cystic renal cell carcinoma but avascular with smooth contours
  • May calcify
  • Hemorrhage may cause acute pain
Gross description
  • Thin walled cortical cysts, measuring up to 10 cm, which are filled with clear yellow fluid
Gross images

Images hosted on other servers:

Simple cyst of upper pole

Large cyst

Multiple, smooth renal cysts filled with serous fluid

Solitary, smooth
kidney cyst
(lower pole) filled
with serous fluid

Large cortical cysts with dark red blood

Microscopic (histologic) description
  • Single layer of cuboidal, flattened or atrophic epithelium
  • May have thickened walls with hemosiderin laden macrophages and atrophic epithelium
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