Lung - nontumor
Cystic disease / congenital anomalies
Cystic adenomatoid malformation

Author: Elliot Weisenberg, M.D. (see Authors page)

Revised: 21 February 2017, last major update August 2011

Copyright: (c) 2003-2017, PathologyOutlines.com, Inc.

PubMed search: cystic adenomatoid malformation [title] lung

Cite this page: Cystic adenomatoid malformation. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/lungnontumorcysticadenomatoid.html. Accessed April 30th, 2017.
Definition / general
  • Rare hamartomatous disorder of variably sized cysts; 1 per 25,000 births
  • Also called congenital pulmonary airway malformation because not all lesions are cystic or adenomatoid
Classification
  • Type 0: 1% - 3%, small / firm lungs, formerly called acinar dysplasia; associated with other malformations; incompatible with life (Pediatr Crit Care Med 2007;8:580)
  • Type I: 60% - 70%, large cysts up to 10 cm lined by pseudostratified ciliated cells interspersed with mucus cells; may appear in older children and adults; good prognosis since can resect; cartilage inconspicuous to absent; shows lepidic growth within cysts and adjacent lung, resembling bronchioalveolar carcinoma
  • Type II: 10% - 15%, small cysts up to 2 cm, resemble dilated bronchioles separated by normal alveoli; very little if any cartilage; rare, if any mucus cells; associated with other malformations; poor prognosis
  • Type III: 5%, solid gross appearance, excess bronchiolar structures separated by small air spaces with cuboidal epithelium resembling fetal lung; usually occupies entire lobe, may involve multiple lobes, unilateral or bilateral, left lower lobe most commonly involved; poor prognosis
  • Type IV: 15%, large cysts up to 10 cm lined by flattened epithelium; good prognosis; similar to grade 1 pleuropulmonary blastoma although less cellular; sample generously to rule out blastoma
Clinical features
  • Associated with stillbirth, neonatal distress and bronchial atresia
  • May develop with and be related to other congenital or acquired lung conditions (Arch Pathol Lab Med 2002;126:934)
  • May regress spontaneously
Case reports
Treatment
Gross images

Images hosted on other servers:

Type I

Type II

Type IV

Microscopic (histologic) description
  • Variably sized cysts lined by "adenomatoid," columnar-type epithelium
Microscopic (histologic) images

Images hosted on other servers:

Type I


Type II

Molecular / cytogenetics description
Additional references