Respiratory pathology

Question 1

Emphysema, caused by smoking

Answer 1

Centriacinar emphysema, most severe in upper lobes.

Pollutants in smoke lead to excessive inflammation and protease-mediated damage.

Question 2

Empysema, caused by A1AT deficiency

Answer 2

Panacinar emphysema, most severe in lower lobes.

Associated with liver cirrhosis (mutant A1AT accumulates in ER of hepatocytes and stains pink with PAS)

Question 3

Kartagener syndrome

Answer 3

Inherited defect of the dynein arm, which is necessary for ciliary movement.

Associated with sinusitis, bronchiectasis, situs inversus, and infertility.

Question 4

Coal Worker’s Pneumoconiosis

Answer 4

Pneumoconiosis (interstitial fibrosis) caused by exposure to carbon dust

Diffuse fibrosis (“black lung”)

Caplan syndrome (pneumoconiosis with RA)

Question 5

Silicosis

Answer 5

Pneumoconiosis (interstitial fibrosis) caused by exposure to silica; sandblasters and silica miners

Silica impairs formation of phagolysosomes in macrophages, leading to an increased risk of TB (upper lobes of lung)

Silica and coal are from the “base” (earth) but affect the “roof” (upper lobes). The opposite of asbestos.

Question 6

Berylliosis

Answer 6

Pneumoconiosis (interstitial fibrosis) caused by exposure to beryllium; miners and aerospace workers

Noncaseating granulomas in the lung, hilar LNs, and systemic organs (similar to sarcoidosis); increased risk of lung cancer

Question 7

Asbestosis

Answer 7

Pneumoconiosis (interstitial fibrosis) caused by exposure to asbestos

Lung carcinoma is more common than mesothelioma in exposed individuals.

Asbestos bodies - long, golden-brown fibers with associated iron

Asbestos is from the roof but affects the “base” (of the lungs)

Question 8

Primary pulmonary hypertension

Answer 8

Caused by inactivating mutation of BMPR2, leading to proliferation of vascular smooth muscle.

Young adult females

Question 9

Bronchial hamartoma

Answer 9

Benign tumor composed of lung tissue and cartilage, often calcified on imaging.

Common cause of benign “coin-shaped” lung lesion (in addition to granulomas of TB and Histo)

Question 10

Small cell carcinoma

Answer 10

Poorly differentiated small cells that arise from neuroendocrine (Kulchitsky) cells).

Common in male smokers

Centrally-located

ADH, ACTH, Eaton-Lambert syndrome

Amplification of myc gene is common

Treat with chemo (not usually amenable to surgical resection, unlike non-small cell carcinomas)

Question 11

Squamous cells carcinoma

Answer 11

Keratin pearls and intercellular bridges

Most common tumor in male smokers

Centrally-located

PTHrP

Question 12

Adenocarcinoma

Answer 12

Glands and mucin production.

Most common tumor in nonsmokers and female smokers.

Activating mutations include k-ras, EGFR, ALK.

Hypertrophic osteoarthropathy (clubbing)

Question 13

Large cell carcinoma

Answer 13

Poorly differentiated large cells (plemormorphic giant cells); no keratin pearls or intercellular bridges (SCC); no glands or mucin (adenocarcinoma)

Associated with smoking

Central or peripheral location

Poor prognosis

Question 14

Bronchioloalveolar carcinoma

Answer 14

Columnar cells that grow along preexisting bronchioles and alveoli; arises from Clara cells

Not related to smoking

Peripherally located (like adenocarcinoma)

May present with pneumonia-like consolidation on imaging

Question 15

Carcinoid tumor of the lung

Answer 15

Well-differentiated neuroendocrine cells that stain positive with chromogranin; nests of neuroendocrine cells

Not related to smoking

Classically forms a polyp-like mass in the bronchus when centrally-located; may also be found in the periphery

Question 16

Risk factors for neonatal respiratory distress syndrome

Answer 16

Prematurity

Maternal diabetes (increase fetal insulin)

C-section delivery (decrease release of fetal glucocorticoids)

Therapeutic supplemental O2 can result in retinopathy of prematurity and bronchopulmonary dysplasia