My study notes for all pathologists

1. FLASHPATH
H A Z E M A L I

2. BRONCHOGENIC
CYSTS
H A Z E M A L I

3. 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
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

4. 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

5. 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

6. 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

7. 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

8. DIFFERENTIAL DIAGNOSIS
I 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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10. THANK YOU
H A Z E M A L I