Pleural and Mediastinal Pathology - Rao

Question 1

What is a pleural effusion?

What volume of fluid defines a pleural effusion?

Describe some processes that cause pleural effusion

Answer 1

Accumulation of fluid in the pleural space

15 mL

Secondary to: increased hydrostatic pressure (CHF, lymphatic blockage), decreased osmotic pressure (nephrotic syndrome), increased vascular permeability (pneumonia)

Question 2

Describe the clinical manifestations of pleural effusion

Answer 2

dyspnea, pleuritic pain, cough, enlarged hemithorax, dullness on percussion, decreased or absent breath sounds, compression of the lung (atelectasis)

Question 3

Name (4) systemic conditions that may cause pleural effusion

Answer 3

congestive heart failure

cirrhosis

nephrotic syndrome

collagen vascular diseases

Question 4

What is the treatment of choice for empyema (pyothorax)

Answer 4

Surgical decortication

Organization of the infection and purulent exudate produces adhesions and loculations that limit lung expansion, necessitating surgical removal

Question 5

Name some underlying conditions leading to hydrothorax

Answer 5

Cardiac failure, pulmonary congestion, edema, cirrhosis, uremia, renal failure

Question 6

Name some underlying conditions leading to hemothorax

Answer 6

ruptured aortic aneurysm, trauma

Question 7

Damage to which structure may lead to chylothorax?

What else might cause chylothorax?

Answer 7

Thoracic duct

lymphatic occlusion secondary to malignancy may also lead to chylothorax

Question 8

Describe the clinical symptoms of pneumothorax

Answer 8

Chest pain, dyspnea

Absent breath sounds on auscultation

hyper-resonant percussion

contralateral deviation of the trachea

atelectasis

marked respiratory distress

Question 9

Describe the common etiologies of spontaneous pneumothorax

Answer 9

often idiopathic

secondary to rupture of a pleural bleb or bulla (often in a young patient)

Bronchopleural fistula or bullous emphysema

Question 10

Describe the presenting symptoms and etiology of tension pneumothorax

What is observed on CXR?

Answer 10

sudden onset of respiratory distress secondary to a chest wall defect (penetrating trauma)

Pneumothorax and collapsed lung with trachea deviated to the contralateral side

Question 11

What is a pleural fibroma? Describe it.

Answer 11

Rare, solitary fibrous tumor of the lung

well circumscribed, polypoid, pedunculated

cured by simple excision

associated with hypoglycemia and clubbing of the fingers

Question 12

What cell type proliferates in malignant mesothelioma?

What is the most common underlying etiology?

Answer 12

Neoplastic proliferation of mesothelial cells lining the serosal surfaces

Idiopathic or asbestos exposure (~50% each)

Question 13

Describe the clinical symptoms of mesothelioma

What is the prognosis?

Answer 13

• insidious, slow-growing neoplasm
• recurrent pleural effusions
• chest pain and dyspnea (advanced)
• pulmonary fibrosis (20%)

Median survival is 18 months

Question 14

Describe the gross morphological appearance of pleural mesothelioma

Name the two histological subtypes of malignant mesothelioma

Answer 14

Rind of fibrous tissue encasing the entire lung with little-to-no invasion of the parenchyma

Histological: epithelioid type or spindle cell type

Question 15

What is more common - primary lung malignancy or metastatic tumor?

Answer 15

metastatic

Question 16

Name (5) organisms that communly underly granulomatous mediastinitis

Answer 16

histoplasmosis

tuberculosis

cryptococcus

atypical mycobacteria

aspergillosis

Question 17

Neurogenic tumors are most commonly found in what part of the mediastinum?

Answer 17

posterior

Question 18

Congenital cysts:

1. unilocular or multilocular?
2. patient age range?
3. contents?

Answer 18

1. unilocular
2. children aged 5-15 years
3. lined with simple cuboidal epithelium and filled with serous fluid

Question 19

Thymic hyperplasia is commonly associated with what autoimmune disorder?

Answer 19

myasthenia gravis

Question 20

What is myasthenia gravis?

What are its symptoms?

What mediastinal disorders is it associated with?

Answer 20

Auto-antibodies to the ACh receptors in the neuromuscular junction - due to defective conrontation between ACh-secreting cells with T-lymphocytes in the thymus

Sx: weakness, fatigability, ptosis, diplopia

Associated with: thymic hyperplasia, thymoma, thymic carcinoma

Question 21

What is a thymoma?

Describe the symptoms

Answer 21

neoplastic proliferation of thymic epithelial cells

usually contains abundant immature T-cells (not part of the tumor)

Frequently associated with myasthenia gravis

slow-growing, rarely metastasizes

Sx: usually asymptomatic, may include cough, dyspnea, chest pain, superior vena cava syndrome, and paraneoplastic syndromes

Question 22

Describe the cell type found in each of the following histological classifications of thymomas

• Type A
• Type B
• Type AB

Answer 22

• Type A: spindle cells
• Type B: round cells
• Type AB: mixture of both round and spindle cells

Question 23

Compare the prognosis of encapsulated and non-encapsulated thymomas

Answer 23

encapsulated: cured by complete surgical excision

non-encapsulated: may recur repeatedly and eventually metastasize. Recurrence may lead to thymic carcinoma

Question 24

Describe the histologic features of thymic carcinoma

Answer 24

No specific or defining features

Closely resembles cell types found in carcinomas of other organs - therefore a diagnosis of exclusion