Chapter 22 - Lungs Flashcards

1
Q

What are the four principal components of the lungs?

A

Large airways (bronchi)

Small airways & air spaces (bronchioles & alveoli)

Interstitium

Vessels

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2
Q

Describe the morphologic appearance of bronchi.

A

Ciliated or columnar epithelium with goblet cells. Goblet cell metaplasia can indicate irritation, as can squamous cell metaplasia.

Also note seromucinous glands, cartilage, smooth muscle, and bronchial arteries.

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3
Q

Describe the morphologic appearance of bronchioles.

A

Cuboidal epithelium without goblet cells.

Clara cells, which are difficult to see.

No cartilage.

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4
Q

Describe the morphologic appearance of alveoli.

A

Thin walls lined by flat type I epithelium. Alveolar macrophages scattered throughout.

Cuboidal epithelium indicates type II hyperplasia, seen in inflammation/repair.

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5
Q

Describe the morphologic appearance of vessels

A

Pulmonary arterioles: Run with bronchioles, two elastic layers on Movats stain.

Veins: Run in interlobular septa, one irregular elastic lamina.

Lymphatics: Run with arteries, veins, and in pleura.

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6
Q

What is Movats stain, and what does it paint?

A

A supplemental stain for fibrotic lung.

Elastic laminae - Black

Hyaluronic acid - Aqua blue

Mature collagen - Yellow

Smooth muscle - Dull red

Fibrinoid necrosis - Bright red

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7
Q

What are the three phases of injury response in lung?

A

Acute, subacute, chronic

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8
Q

How does acute lung injury manifest?

What is acute interstitial pneumonitis, and how does it appear?

A

As diffuse alveolar damage.

AIP has no identifiable factor. It features interstitial edema/hemorrhage, hyaline membrane formation, type II hyperplasia, and fibrin thrombi.

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9
Q

How does subacute lung injury manifest?

A

Fibroblast foci form in alveoli and bronchioles. This is indistinguishable from BOOP.

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10
Q

How does chronic lung injury manifest?

A

With end fibrosis and honeycomb lung. “Usual interstitial pneumonia” is the nonspecific pattern, and is called “idiopathic pulmonary fibrosis” when no etiology is known.

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11
Q

Describe the appearance of usual interstitial pneumonia.

A

Temporal heterogeneity; meaning seeing acute / subacute / chronic injury in the same tissue.

Prominent interstitial fibrosis, distortion of airspaces, with fibroblast foci, acute & chronic inflammation.

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12
Q

What are the two forms of allergic lung disease, and what are some examples?

A

IgE-mediated: Asthma, ABPD, eosinophilic pneumonias

Cell-mediated hypersensitivity: Pneumonconioses, patchy chronic interstitial pneumonia, foci of BOOP.

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13
Q

What lung disease patterns are seen in smokers?

A

DIP (desquamative interstitial pneumonitis)

Respiratory bronchiolitis

Langerhans cell histiocytosis

Usual interstitial pneumonia

Obstructive lung diseases: Emphysema and chronic bronchitis

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14
Q

What is DIP?

A

Desquamative interstitial pneumonitis

Alveolar macrophages pack the alveoli, usually in smokers but in other disease processes as well.

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15
Q

How does langerhans cell histiocytosis appear?

Why is this in the lung chapter?

A

Collections of histiocytes (pale nuclei with folds and creases), sometimes with eosinophils (“eosinophilic granuloma”).

Half of cases occur in adults, generally as isolated pulmonary diseases of smokers.

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16
Q

What two epithelia do lung cancers arise from?

A

Respiratory epithelium

Squamous metaplastic epithelium

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17
Q

What is atypical adenomatoid hyperplasia, and how does it appear?

A

A small focus (~1cm) of type II hyperplasia, which is plump cuboidal to columnar eosinophilic. This is probably a dysplastic lesion and results from chronic irritation.

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18
Q

Describe the appearance and location of squamous carcinoma.

A

Usually keratinizing with dense pink cytoplasm, keratin whorls, and distinct cell borders.

Arises from squamous metaplasia, usually in the major bronchi. Therefore, it is central or hilar.

19
Q

How is squamous carcinoma graded?

Name six variants.

A

Well / Moderately / Poorly differentiated

Nonkeratinizing, basaloid, small cell (no neuroendocrine stainin!), spindle cell, clear cell, intrabronchial papillary

20
Q

What are the types and patterns of lung adenocarcinoma?

A

Acinar, tubular, papillary, solid. Lepidic?

Can be mucinous or nonmucinous.

21
Q

Describe the appearance of bronchioalveolar carcinoma.

A

Columnar and usually eosinophilic cells outlining the air spaces. Can be mucinous or nonmucinous.

Note: Do not call unless lesion is ENTIRELY sampled.

22
Q

What is large cell undifferentiated carcinoma?

Lymphoepithelioma-like carcinoma?

A

Large cell: Undifferentiated with ugly appearance and no recognizable features. Can be giant cell.

Lymphoepithelioma-like: Scattered large malignant cells in a sea of lymphocytes.

23
Q

Describe and contrast carcinoid and atypical carcinoid tumors.

A

Carcinoid: Well-differentiated neoplasm with classic neuroendocrine features. Can metastasize to lymph nodes.

Atypical carcinoid: Increased mitoses (2-10/10hpf), hyperchromatic nuclei, and/or necrosis.

24
Q

Describe small cell neuroendocrine carcinoma of the lung.

A

High-grade neoplasm with small cell morphology, hyperchromatic nuclei, no nucleoli. Syncytial appearance with nuclear molding, crush artifact.

25
Q

Describe large cell neuroendocrine tumor.

A

A high-grade neuroendocrine neoplasm, with large cytoplasm. Neuroendocrine features can be architectural or nuclear, but staining should be positive.

26
Q

What is non-small cell carcinoma with neuroendocrine features?

A

A tumor that looks like NSCLC but is chromogranin-positive.

27
Q

What is a hamartoma?

A

Tumor-like mass composed of mixture of normal organ elements (usually cartilage, fat, smooth muscle, and epithelium)

28
Q

Describe carcinosarcoma of lung.

A

A biphasic lesion, with a carcinoma and usually an osteosarcoma or chondrosarcoma.

29
Q

What is pulmonary blastoma?

Pleuropulmonary blastoma?

A

Pulmonary blastoma: A form of carcinosarcoma in adults. Epithelial component resembles fetal lung, stromal component may be adult-type or immature mesenchyme.

Pleuropulmonary blastoma: Embryonal-type sarcoma of infancy which has only cartilage and/or rhabdomyoblastic elements (no carcinoma)

30
Q
A

Normal bronchus

  1. Ciliated columnar epithelium
  2. Goblet cells
  3. Cartilage
  4. Smooth muscle
  5. Bronchial artery branches
31
Q
A

Bronchioles & alveoli

B: Bronchiole, lined by cuboidal epithelium and smooth muscle.
A: Arteriole
V: Venule, running in septa
Arrow: Alveolar walls
Arrowhead: Alveolar macrohpages

32
Q
A

Movats stain of lung.

A: Artery with two elastic laminae (arrowheads)
V: Vein with one elastic lamina (arrow)

33
Q
A

Diffuse alveolar damage.

Asterisk: Fluid and blood in interstitial spaces
Arrow: Thick pink hyaline membranes

34
Q
A

Fibroblast foci

Left: On H&E, they appear myxoid and pale
RIght: On Movats, they appear turquoise

35
Q
A

Usual interstitial pneumonia

Arrowhead: Interstitial thickening & fibrosis
Arrow: Chronic inflammation
Inset: Irregularly shaped alveolar spaces with type II hyperplasia.

36
Q
A

Reactive epithelium overlying a carcinoid tumor.

Arrow: Note presence of cilia, marking benign epithelium

37
Q
A

Atypical adenomatoid hyperplasia

Arrow: Interstitial inflammation
Arrowhead: Type II hyperplasia

38
Q
A

Squamous cell carcinoma

Left: Moderately differentiated, with bright dense pink cytoplasm (arrow).

Right: Basaloid squamous cell carcinoma, with rounded nests of blue tumor cells and central necrosis (asterisk).

39
Q
A

Sarcomatoid carcinoma. Note sheets of spindled cells with prominent nucleoli.

Arrow: Mitoses

40
Q
A

Lung adenocarcinoma.

Arrow: Cribriforming
Arrowhead: Small glands in a desmoplastic stroma

41
Q
A

Bronchoalveolar carcinoma

Note lining of the air spaces with malignant cells but with no invasion or mass effect.

42
Q
A

Carcinoid tumor

Note nested & trabecular pattern of cells with neuroendocrine chromatin (speckled, without nucleoli)

43
Q
A

Small cell carcinoma

Note nuclear molding and crowded cells with little cytoplasm. Neuroendocrine nuclei. Necrosis and mitoses (arrow) are common.