Mediastinum
Thymus
Thymic dysplasia

Author: Hanni Gulwani, M.D. (see Authors page)

Revised: 14 June 2018, last major update December 2012

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

PubMed Search: Thymic dysplasia

Cite this page: Gulwani, H. Thymic dysplasia. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/mediastinumthymicdysplasia.html. Accessed July 21st, 2018.
Definition / general
  • Congenital thymic alteration due to developmental arrest
  • Lack of differentiation of thymic epithelium, responsible for absence of Hassall corpuscles, is main feature (Histopathology 1992;21:499)
Clinical features
  • Associated with severe combined immunodeficiency syndrome, ataxia telangiectasia, chromosomal instability syndromes, Nezelof syndrome (Arch Pathol Lab Med 1987;111:1118)
  • Incomplete form of DiGeorge syndrome is congenital anomaly with a constellation of findings that includes thymic hypoplasia (J Cutan Pathol 2008;35:380); complete form has absent thymus
Gross description
  • Small thymus (< 5 g)
Microscopic (histologic) description
  • Tubules and rosettes of primitive appearing epithelium without segregation into cortical and medullary regions
  • No Hassall corpuscles, no / rare lymphocytes
Differential diagnosis