Mediastinum
Nonneoplastic
Acute thymic involution


Topic Completed: 1 December 2012

Minor changes: 20 November 2019

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PubMed Search: Acute thymic involution

Hanni Gulwani, M.B.B.S.
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Cite this page: Gulwani H. Acute thymic involution. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/mediastinumacutethymicinvolution.html. Accessed May 27th, 2020.
Definition / general
  • Due to stress (chronic debilitating disease), HIV or other infections, prolonged protein malnutrition and immunosuppressive or cytotoxic drugs, graft versus host reaction
  • Seen in newborn infants with chorioamnionitis and sepsis
  • Thymus size is significantly reduced in preterm infants born to mothers with subclinical, histologically proven chorioamnionitis (Hum Pathol 2000;31:1121)
Microscopic (histologic) description
  • Preservation of lobular architecture and Hassall corpuscles but marked lymphocyte depletion (particularly with HIV)
  • Vessels are large compared to size of lobules
  • Frequent plasma cells, fibrohyaline changes of basement membrane of vessels and thymic epithelium
  • HIV patients also have effacement of corticomedullary junction and inconspicuous Hassall corpuscles
Differential diagnosis
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