Lung Pathology

Chronic Interstitial (Restrictive, Infiltrative) Lung Diseases

Feb. 28. 2016
Ch. 12 p (459 – 512

Acute respiratory distress syndrome Obstructive lung diseases Restrictive lung diseases Vascular diseases
Respiratory Pathology Outline

Restrictive Lung Disease

Bilateral, patchy, & chronic involvement of the pulmonary C.T., mainly the alveolar walls.

Chronic Interstitial Lung Diseases

Diffuse interstitial fibrosis of the lung cause restrictive lung diseasesreduced lung compliance, (stiff lung) FEV / FVC is normal.Caused by heterogeneous diseasesInjury to the alveoli, activated macrophages release TGF-β.IPF; patchy fibrosis with cystic spaces (honeycomb lung). Also known as usual interstitial pneumonia (UIP).

Pathways of macrophage activation

Th2, Eosinophils, Mast cells
Th1

Schematic representation of the pathogenesis IPF

REDUCED COMPLIANCE (stiff lung), reduced gas exchange Diffuse Honeycomb FIBROSING GRANULOMATOUS EOSINOPHILIC SMOKING RELATED PAP (Pulmonary Alveolar Proteinosis
Restrictive lung diseases

FibrosingUsual interstitial pneumonia (idiopathic pulmonary fibrosis)Nonspecific interstitial pneumoniaCryptogenic organizing pneumoniaAssociated with collagen vascular diseasePneumoconiosisAssociated with therapies (drugs (amiodarone, bleomycin, methotrexate) & radiation)GranulomatousSarcoidosisHypersensitivity pneumoniaEosinophilicLoeffler syndromeDrug allergy–relatedIdiopathic chronic eosinophilic pneumoniaSmoking-RelatedDesquamative interstitial pneumoniaRespiratory bronchiolitis Major Categories of Chronic Interstitial Lung Disease


Idiopathic pulmonary fibrosis, (IPF; usual interstitial pneumonitis [UIP], honeycomb fibrosis) radiograph There are increased brighter interstitial markings marked in lower lung fields.


Idiopathic pulmonary fibrosis, CT image; Shows very prominent bright interstitial markings in the posterior lung bases. There are also smaller darker lucent areas that represent honeycomb change, a characteristic feature of usual interstitial pneumonitis.

Normal lung, CT image

R
L
A
V



Honeycomb change, grossRegardless of the cause of restrictive lung diseases, many eventually lead to extensive pulmonary interstitial fibrosis. The gross appearance shown n a patient with organizing DAD is known as “honeycomb lung”

IPF; Honeycomb change; gross

Idiopathic pulmonary fibrosis, (IPF; usual interstitial pneumonitis (UIP), honeycomb fibrosis), microscopic There is dense fibrous connective tissue ( ) surrounding residual airspaces filled with pink proteinaceous fluid The interstitial infiltrate; Lymphocytes, plasma cells, mast cells, and eosinophils
Fluid
Fibrosis
L, Eosino, Mast

IPF: tons of fibrosis

Interstitial fibrosis, microscopic A trichrome stain highlights in blue the collagenous interstitial connective tissue of pulmonary fibrosis

NON-SPECIFIC INTERSTITIAL PNEUMONIA (NSIP)

a chronic bilateral interstitial lung disease of unknown etiology. it carries a much better prognosis than that for IPF. cellular and fibrosing patterns No honeycombing

CRYPTOGENIC ORGANIZING PNEUMONIA (COP)

Some alveolar spaces are filled with balls of fibroblasts. Although compressed, adjacent alveoli are relatively normal Rx; Steroids


“COLLAGEN” VASCULAR DISEASES Rheumatoid ArthritisSLE (“Lupus”)Progressive Systemic Sclerosis (Scleroderma)

Coal

bagasse
asbestos
silica nodules
Pneumoconioses
Size matters (1-5 μm particles are worst) Sandblasting, quarrying, mining, stone cutting, ceramics
Mining, & fabrication of materials, insulation


Coal worker’s pneumoconiosis, microscopicAsymptomatic anthracosis, to simple coal worker’s pneumoconiosis (coal macules or nodules, and centrilobular emphysema), to progressive massive fibrosis (PMF) There is no increased risk for lung cancer. Emphysema


Silicosis, microscopic; The most common pneumoconiosis. Silicotic nodules (arrow ) (bundles of collagen & a surrounding inflammatory reaction) Range from asymptomatic silicotic nodules to PMF +/- Calcification (egg shell calcification) There is anincrease risk for TB & lung cancer .


Asbestos fibers


Ferruginous bodies, microscopic; The long, thin asbestos fiber coated with iron and calcium, called a ferruginous body, several of which are seen here with a Prussian blue iron stain

QUIZ

GRANULOMATOUS
SARCOIDOSIS, i.e., Non-caseating granulomas (Idiopathic)HYPERSENSITIVITY (Dusts, bacteria, fungi, Farmer’s Lung, Pigeon Breeder’s Lung)

SARCOIDOSIS

LN & Lung, but eye, skin or….UNKNOWN ETIOLOGYImmune, Genetic factorsYOUNG BLACK WOMENfever, cough, dyspnea, night sweats, and weight losscan lead to restrictive lung diseaseMinimal pulmonary disease that resolves with corticosteroid Rx. CXR: hilar LN & pulmonary interstitial fibrosis


Sarcoidosis in mesenteric lymph node; Non-Caseating Granulomas are the RULE“Asteroid” bodies within these granulomas are virtually diagnostic

“Caseating” and a “non-caseating” granuloma