Adrenal gland and paraganglia
Adrenal hyperfunction / hyperplasia
Micronodular hyperplasia

Author: Nat Pernick, M.D. (see Authors page)

Revised: 14 January 2016, last major update February 2013

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

PubMed Search: Micronodular hyperplasia
Cite this page: Micronodular hyperplasia. website. Accessed November 18th, 2018.
Definition / general
  • Small (less than 0.5 cm) nodules of histologically unremarkable adrenocortical tissue in adrenal cortex or protruding into adjacent adipose tissue
  • Often multiple and bilateral; microscopic or grossly visible
  • Associated with older age, hypertension and diabetes
  • At autopsy, present in 3% of all ages, 20% with hypertension and 29% of women with mean age 81 years
  • May represent localized overgrowth of adrenocortical cells
  • Usually non-functional; no clinical significance
Gross description
  • Unencapsulated, may protrude into capsule and may completely detach from capsule
Microscopic (histologic) description
  • Cortical cells may stream into periadrenal fat
  • Adrenal arteries often are hyalinized with intimal proliferation that causes luminal obliteration
  • May have neuromelanin pigment; may undergo myelolipomatous or osseous metaplasia
Differential diagnosis