Kidney nontumor / medical renal

Developmental & cystic diseases

Medullary sponge kidney

Last author update: 1 December 2011
Last staff update: 15 June 2022

Copyright: 2003-2023,, Inc.

PubMed Search: Medullary sponge kidney

Mandolin S. Ziadie, M.D.
Page views in 2022: 1,106
Page views in 2023 to date: 944
Cite this page: Ziadie MS. Medullary sponge kidney. website. Accessed September 30th, 2023.
Definition / general
  • Sporadic cystic disease characterized by bilateral cystic dilations of medullary collecting ducts; normal cortex
  • 1 per 5000 births; no gender preference; not familial
  • Associated with hemihypertrophy of body (25% of cases), Marfan's, Caroli's and Ehlers-Danlos
Clinical features
  • Usually presents in adulthood
  • Patients are usually asymptomatic with normal renal function
  • Calcifications on Xray, stones, hematuria and infection at age 30+ years
  • Does not progress to end stage renal disease
  • Diagnosed with intravenous pyelography
  • Cranberry juice to maintain urinary acidity
  • Nephrectomy is NOT recommended
Gross description
  • Normal sized kidneys with multiple, small cysts in medullary pyramids and papillae, giving medulla a sponge-like appearance
  • Most often bilateral
Gross images

Images hosted on other servers:

Cysts of inner medullary and papillary region

Extensive cysts communicating with each other

Papillae are interspersed due to variably sized cysts

Small cysts with stones, papillae on right is not affected

Numerous medullary cysts and isolated cortical cyst

Cysts at corticomedullary junction

Microscopic (histologic) description
  • Medullary cysts lined by cuboidal epithelium or urothelium
  • May have concretions adherent to cyst wall
  • Often severe inflammation and scarring in interstitium, often with tubular atrophy near papillary tips
Microscopic (histologic) images

Images hosted on other servers:

Cysts in papilla

With microlithiasis and chronic pyelonephritis

Cortical cyst, multiple cysts
at the corticomedullary
junction and atypically
located papillary cyst

Additional references
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