FLASHPATHH A Z E M A L I

BRONCHOGENIC CYSTS

H A Z E M A L I

CLINICAL• Congenital anomalous budding of the primitive foregut during lung

development– But not connected to tracheobronchial tree

• Although relatively rare, represent the most common cystic lesion of the mediastinum

– Most commonly at middle mediastinum “at level of carina”

• Seen in children or young adults; more common in males

• Present as Space occupying lesion:– Recurrent infection– Compression to surrounding “bronchi”– Or asymptomatic

GROSS

Cyst:• Round to oval• Uni- or multi-locular• Range from 1 to 10cm• Smooth wall• Contain clear fluid or mucus• No communication with tracheobronchial tree

MICROSCOPY• Similar to Bronchial wall:

– Lining:• Respiratory epithelium

– “Pseudostratified columnar ciliated”– Wall:

• Smooth muscle• Cartilage• Submucosal glands

• If infected may show:– Squamous metaplasia– Chronic inflammation– Fibrosis

DIFFERENTIAL DIAGNOSIS“ O t h e r m e d i a s t i n a l c y s t s ”

• Esophageal cyst:– Lined by squamous epithelium– Wall has more developed, double- layer muscular layer– No cartilage

• Gastro-enteric cyst:– Lined by gastric or intestinal mucosa– No cartilage

• Thymic cyst:– Lined by flat, cuboidal, columnar, or squamous epithelium– Wall may show chronic inflammation, cholesterol clefts, or thymic tissue remnants– No cartilage or smooth muscle

DIFFERENTIAL DIAGNOSIS“ O t h e r m e d i a s t i n a l c y s t s ”

• Cystic Teratoma:– Heterogeneous tissue components from ectoderm, endoderm, and

mesoderm

• Pericardial cyst:– Lined by single layer of mesothelial cells overlying loose connective tissue

DIFFERENTIAL DIAGNOSISI f o c c u r r e d n e a r l u n g“ O t h e r c y s t i c l u n g d i s e a s e s ”

• Congenital:– Pulmonary sequestration– Congenital pulmonary cysts– Congenital pulmonary airway malformation– Congenital lobar emphysema

• Acquired:– Emphysema– Healed abscess– Honeycombing

• Mixed:– Cystic fibrosis

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