Adrenal gland & paraganglia

Adrenal hyperfunction / hyperplasia

Micronodular hyperplasia

Topic Completed: 1 February 2013

Minor changes: 4 June 2019

Copyright: 2003-2019,, Inc.

PubMed Search: Micronodular hyperplasia

Nat Pernick, M.D.
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Cite this page: Pernick N. Micronodular hyperplasia. website. Accessed December 3rd, 2021.
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
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