Kidney tumor
Cystic nonneoplastic lesions
Medullary sponge kidney

Author: Mandolin Ziadie, M.D.

Revised: 19 April 2018, last major update December 2011

Copyright: (c) 2003-2018,, Inc.

PubMed Search: Medullary sponge kidney [title]

Cite this page: Ziadie, M.S. Medullary sponge kidney. website. Accessed October 20th, 2018.
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