Congenital Pulmonary Airway Malformation in an Adult Male: A Case Report with Literature Review

Table 1

	Type 0	Type 1	Type 2	Type 3	Type 4
Also called	Acinar dysplasia		Intermediate	Solid
Frequency	1–3%	50–65%,	20–25%,	8%	10%
Relative frequency	Fifth	Most common	Second most common	Fourth	Third
Presumed site of development	Tracheobronchial	Bronchial or bronchiolar	Bronchiolar	Bronchiolar/alveolar	Distal acinar
Clinical presentation as adult	No reports	If smaller, may present later in life with recurrent infections (36 reported cases) [2, 15–19]	10 previously reported cases [2, 15]	No reports	One case [18]
Cyst size	0.5 cm	2 to 10 cm	<2–2.5 cm	<0.2 cm	Varying, up to 7 cm
Cyst lining	Ciliated pseudostratified	Cuboidal to pseudostratified columnar	Cuboidal to columnar, ciliated, may resemble ectatic bronchiole-like structures	Ciliated cuboidal, resembling fetal lung in canalicular stage	Types 1 and 2 alveolar, resembling bullous emphysema
Cyst wall	Connective tissue and vasculature	Broad fibromuscular connective tissue	Small amount of fibrovascular connective tissue	Usually solid	Thin, uniform, central loose vascular tissue
Other histologic findings	Bronchial-like structures, cartilaginous airways, smooth muscle	Cartilage islands, one-third showing mucous cells, sometimes in clusters	Entrapped bronchovascular bundles near edge of lesion; occasionally mature skeletal muscle	Solid, curved channels	Large cysts usually in peripheral lung
Risk of malignancy	Not identified	Bronchioloalveolar; Carcinoma	Not identified	Not identified	Must rule out pleuropulmonary blastoma

Adapted from [2, 7, 10, 11].