The Lung Part 11

Question 1

The most common site of metastatic neoplasms

Answer 1

the lung!!

• Both carcinomas and sarcomas arising anywhere in body may spread to lungs via blood or lymphatics or by direct continuity
• Growth of contiguous tumors into lungs occurs most often with ESOPHAGEAL carcinomas and mediastinal lymphomas

Question 2

Morphology of metastatic tumors

Answer 2

• variable pattern
• usually multiple discrete nodules (CANNONBALL LESIONS) scattered through all lobes, more at periphery
• Other patterns include: solitary nodule, endobronchial, pleural, pneumonic consolidation, and combos of these
• Foci of lepidic growth similar to adenocarcinoma in situ seen occasionally and may be associated with any of the patterns

Question 3

Pathologic involvement of the pleura is most often a

Answer 3

• secondary complication of underlying disease

- secondary infections/ pleural adhesions =common autopsy findings

Question 4

Important PRIMARY disorders of the pleura are (2)

Answer 4

1) primary intrapleural bacterial infections–seeding of this space as isolated focus in transient bacteremia
2) primary neoplasm of the pleura: mesothelioma

Question 5

Pleural effusion

Answer 5

• common manifestation of both primary and secondary pleural diseases–can be inflammatory or not
• usually no more than 15ml of serous, relatively acellular, clear fluid lubricates pleural surface

Question 6

Accumulation of pleural fluid happens in 5 different settings

Answer 6

1) Increased hydrostatic pressure (like CHF)
2) Increased vascular permeability (pneumonia)
3) Decreased osmotic pressure (nephrotic syndrome)
4) Increased intrapleural negative pressure (atelectasis)
5) Decreased lymphatic drainage (mediastinal carcinomatosis)

Question 7

Serous, serofibrinous, and fibrinous pleuritis all have

Inflammatory pleural effusion

Answer 7

• an inflammatory basis

- differ only in intensity and duration of process

Question 8

Most common cause of pleuritis (Inflammatory pleural effusion)

Answer 8

-disorders associated with inflammation of lung like tuberculosis, pneumonia, lung infarcts, lung abscess, bronchiectasis

Question 9

(Other) Causes of serous or serofibrinous pleuritis (Inflammatory pleural effusion)

Answer 9

• Rheumatoid arthritis
• SLE
• Uremia
• Diffuse systemic infections
• Other systemic disorders
• Metastatic involvement of pleura

Question 10

Radiation therapy for tumors in lung or mediastinum cause what kind of pleuritis?

Answer 10

SEROFIBRINOUS PLEURITIS

Inflammatory pleural effusion

Question 11

Usually, the serofibrinous reaction is minimal or maximal?

Answer 11

• usually minimal and fluid exudate is resorbed with either resolution or organization of fibrinous component
• Sometimes, though, large amts of fluid accumulate and compress the lung causing respiratory distress

Question 12

A purulent pleural exudate (EMPYEMA) usually results from

Answer 12

• bacterial or mycotic seeding of the pleural space
• seeding occurs by contiguous spread of organisms from intrapulmonary infection but occasionally can occur through lymphatic or hematogenous dissemination from distant source

Question 13

Rarely, infections below the diaphragm like sub diaphragmatic or liver abscess may extend by

Answer 13

-continuity through the diaphragm into the pleural spaces, more often on the RIGHT SIDE

Question 14

Empyema is characterized by

Answer 14

• loculated, yellow-green creamy pus composed of masses of neutrophils admixed with other leukocytes
• empyema may accumulate in large volumes (unto 500-1000mL), but usually the volume is SMALL and pus is localized
• may resolve but more often, organizes into dense, tough fibrous adhesions that obliterate the pleural space or envelop the lungs; can seriously restrict pulmonary expansion

Question 15

Hemorrhagic pleuritis (Inflammatory pleural effusion)

Answer 15

• see sanguineous inflammatory exudates, is infrequent and is found in hemorrhagic diathesis, rickettsial diseases, and neoplastic involvement of pleural cavity
• sanguineous exudate must be differentiated from hemothorax!!
• Look for EXFOLIATED TUMOR CELLS

Question 16

Noninflammatory collections of serous fluid within pleural cavities (Noninflammatory pleural effusions) are called

Answer 16

-Hydrothorax

Question 17

Hydrothorax

Answer 17

• may be unilateral or bilateral
• fluid is clear and straw colored
• most common cause: cardiac failure so also see pulmonary congestion and edema
• Transudates in other systemic diseases can cause generalized edema like renal failure and cirrhosis of liver

Question 18

Hemothorax

Answer 18

• Escape of blood into the pleural cavity

- fatal complication of ruptured aortic aneurysm or vascular trauma or may occur postopperatively

Question 19

Chylothorax

Answer 19

• accumualation of milky fluid, usually of lymphatic origin in pleuritic cavity
• milky white because contains finely emulsified fats
• most often caused by thoracic duct trauma or obstruction that secondarily causes rupture of major lymphatic ducts
• cause: malignancies that obstruct major lymphatic ducts–these cancers arise within thoracic cavity and invade lymphatics locally but occasionally more distant cancers metastasize via lymphatics and grow within right lymphatic thoracic duct, producing obstruction

Question 20

Pneumothorax

Answer 20

• air or gas in the pleural cavities
• associated w/ emphysema, asthma, and TB
• 3 types: spontaneous, traumatic or therapeutic

Question 21

Spontaneous pneumothorax

Answer 21

• may complicate any form of pulmonary disease that causes rupture of alveolus
• Also caused by abscess cavity that communicates with pleural space or with lung interstitial tissue–may lead to air dissecting through the lung substance or back through the mediastinum (interstitial emphysema) eventually entering pleural cavity

Question 22

Traumatic pneumothorax

Answer 22

-cause: perforating injury to chest wall, but sometimes trauma pierces lung and provides two ways air can get in within pleural spaces

Question 23

Resorption of air in pleural space occurs in what kind of pneumothorax?

Answer 23

-Spontaneous and traumatic pneumothorax if original communication seals itself

Question 24

Spontaneous Idiopathic pneumothorax

Answer 24

• young people
• cause: rupture of small, peripheral, usually apical sub pleural blebs and usually subsides spontaneously as air is resorbed
• Common recurrent attacks which are disabling!

Question 25

Pneumothorax clinical signficance

Answer 25

-similar to fluid collection in that it also causes compression, collapse and atelectasis of lung and lead to respiratory distress

Question 26

Tension pneumothorax

Answer 26

-When defect acts as a flap valve and permits entrance of air during inspiration but fails to permit its escape during expiration, it acts as a pump that creates progressively increasing pressures which can compress vital mediastinal structures and contralateral lung

Question 27

Are primary or secondary tumors of the pleura more common?

Answer 27

-SECONDARY!

Question 28

Most frequent metastatic malignancies of the pleura arise from primary neoplasms of which organs?

Answer 28

• Lung and Breasts!

- but can be from any other organ

Question 29

Ovarian carcinomas metastasis

Question 30

In most metastatic involvements of pleura, what usually happens

Answer 30

• serous or serosanguieous effusion follows that contains neoplastic cells
• so need careful cytologic exam of sediment to Dx

Question 31

Solitary fibrous tumor

Answer 31

• Soft-tissue tumor
• usually occurs in pleura and less commonly in lung
• tumor attached to pleural surface by pedicle
• may be small (1-2cm) or enormous
• remains confined to surface of lung!

Question 32

Morphology of solitary fibrous tumors

Answer 32

• consists of dense fibrous tissue w/occasional cysts filled with viscid fluid
• microscopic: see whorls of reticulin and collagen fibers with interspersed spindle cells resembling fibroblasts
• Rarely is malignant with pleomorphism, mitotic activity, necrosis and large size
• CD34 pos and keratin neg!!!–helps diff from mesotheliomas which show opposite phenotype!!
• NO RELATION TO ASBESTOS!

Question 33

Solitary fibrous tour is highly associated with

Answer 33

• cryptic inversion of chromosome 12 involving genes NAB2 and STAT6
• this rearrangement creates NAB2-STAT6 fusion gene that is unique to solitary fibrous tumors
• encodes chimeric transcription factor–key driver of tumor development

Question 34

Malignant mesothelioma

Answer 34

-higher incidence among ppl w/HEAVY EXPOSURE TO ASBESTOS

Question 35

Thoracic mesothelioma arises from

Answer 35

• either the visceral or parietal pleura
• latent pd of 25-45 yrs for development of asbestos-related mesothelioma
• no increased risk of mesothelioma in asbestos workers who also smoke–in contrast to asbestos related lung carcinoma!–so for asbestos workers, higher risk of dying from lung carcinoma much higher than from mesothelioma

Question 36

Findings/markers for people with mesothelioma

Answer 36

• Asbestos bodies

- Asbestos plaque–marker of asbestos exposure

Question 37

Cytogenetic abnormalities associated with mesothelioma

Answer 37

-homozygous deletion of tumor suppressor gene CDKN2A/INK4a which occurs in 80% of mesotheliomas–involves chromosome 9p which can help distinguish mesothelioma from reactive mesothelial proliferations

Question 38

Morphology of malignant mesotheliomas

Answer 38

• diffuse lesion arising from visceral or parietal pleura that spreads widely in pleural space and is usually associated with extensive pleural effusion and direct invasion of thoracic structures
• affected lung becomes ensheathed by thick layer of soft, gelatinous, grayish pink tumor tissue

Question 39

Microscopically, mesotheliomas may be

Answer 39

• epitheliod, sarcomatoid, or mixed

- bc mesothelial cells have potential to develop as epithelium like cells or mesenchymal stromal cells

Question 40

Epithelioid type of mesothelioma consists of

Answer 40

• cuboidal, columnar or flattened cells forming tubular or papillary structures resembling adenocarcinoma
• Immunohistochemichal stains helpful in distinguishing it from pulmonary adenocarcinoma

Question 41

Most mesotheliomas show strong positivity for

Answer 41

• keratin proteins
• calretinin
• Wilms tumor 1 (WT-1)
• cytokeratin 5/6 and D2-40
• panel above diagnostic along w/clinical S/S in majority

Question 42

Sarcomatoid type of mesothelioma

Answer 42

• Mesenchymal type
• Appears as spindle cell carcinoma resembling fibrosarcoma
• LOWER expression of markers and may only be positive for keratin

Question 43

Mixed (biphasic) type of mesothelioma

Answer 43

-contains both epithelioid and sarcomatoid patterns

Question 44

Clinical course of mesothelioma–symptoms and metastasis

Answer 44

• Chest pain, dyspnea, and recurrent pleural effusions
• concurrent pulmonary asbestosis (fibrosis) present in only 20% with pleural mesothelioma–lung is invaded directly and there is often metastatic spread to hilar lymph nodes and eventually to liver and other distal organs

Question 45

Mesothelioma prognosis and treatment

Answer 45

• 50% die within 12 months of Dx and few survive longer than 2 yrs
• Aggressive Tx (extrapleural pneumonectomy, chemotherapy, radiation therapy) improves poor prognosis in some

Question 46

Mesotheliomas can also arise in what other organs?

Answer 46

• Peritoneum
• Pericardium
• Tunica vaginalis
• Genital tract (benign adenomatoid tumor)

Question 47

Peritoneal mesotheliomas are related to

Answer 47

• heavy asbestos exposure in 60% of MALE pts (much lower in females!)
• In half, remains confined to abdominal cavity but sometimes intestinal involvement leads to death from intestinal obstruction or inanition