Pleural and Mediastinal Pathology Flashcards Preview

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Flashcards in Pleural and Mediastinal Pathology Deck (35)
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1
Q

What can lead to a pleural effusion?

A

Accumulation of fluid (>15mL) in the pleural space secondary to:

  • Increase in hydrostatic pressure
    • congestive heart failure, lymphatic blockage due to tumor
  • Decreased osmotic pressure
    • nephrotic syndrome
  • Increased vascular permeability
    • pneumonia
2
Q

How does a pleural effusion clinically manifest?

A
  • Dyspnea, pleuritic pain, cough
  • Enlarged hemithorax
    • dullness on percussion
    • decreased or absent breath sounds
  • Compression of the lung
    • atelectasis leading to respiratory distress
3
Q

How is a pleural effusion diagnosed and treated?

A
  • Chest X-ray
  • Thoracentesis
  • Analysis of pleural fluid
    • Chemistry
    • Culture
    • Cytology
  • Pleural biopsy (percutaneous, open)
  • Treatment of underlying cause
4
Q

Common Causes of Pleural Effusion:

A
  1. Infections
    • Bacterial pneumonia
    • Viral disease
    • Tuberculosis
  2. Pulmonary embolism
  3. Malignant neoplasms
  4. Trauma
  5. Systemic conditions
    • Congestive heart failure
    • Cirrhosis
    • Nephrotic syndrome
    • Collagen vascular diseases
5
Q

List the different types of pleural effusions:

A
  1. Inflammatory Pleural Effusions:
    • Serofibrinous
    • Suppurative (empyema)
    • Hemorrhagic
  2. Non-Inflammatory Pleural Effusions:
    • Hydrothorax
    • Hemothorax
    • Chylothorax
6
Q

What are causes of inflammatory pleural effusions?

A
  1. Serous, fibrinous and serofibrinous: inflammatory conditions such as pneumonia, T.B., lung infarcts, abscesses
  2. Purulent exudate (empyema): localized accumulation of pus due to organisms
  3. Hemorrhagic pleuritis: coagulopathies, rickettsial disease, malignant neoplasms
7
Q
  • What is an empyema (pylothorax)?
  • What is done to treat it?
A
  • Purulent pleural effusions complicating lung infections
    • pneumococci, staphilococci and streptococci
    • A.k.a. “suppurative pleuritis”
  • Pleural surface is coated by shaggy thick fibrin layer admixed with greenish purulent exudate
  • Organization produces adhesions and loculation circumscribing the pus and limiting lung expansion
  • Surgical decortication is treatment of choice
8
Q

What are the differences between the non-inflammatory pleural effusions?

A
  1. Hydrothorax: clear serous fluid
    • cardiac failure, pulmonary congestion and edema, cirrhosis, uremia, renal failure
  2. Hemothorax: hemorrhagic fluid
    • ruptured aortic aneurysm, trauma
  3. Chylothorax: milky fluid
    • thoracic duct trauma or lymphatics occlusion secondary to malignancy
9
Q
  • What is a pneumothorax?
  • What is it most commonly associated with?
  • What are the two types of pneumothorax?
A
  • Presence of air or gas within the pleural cavity
    • Spontaneous – traumatic – therapeutic
  • Most commonly associated with emphysema, asthma and tuberculosis
  • Two Types:
    1. Spontaneous idiopathic pneumothorax
    2. Tension pneumothorax
10
Q

What mechanisms can form a pneumothorax?

A
  • Perforation of the visceral pleura and entry of air from the lung
  • Penetration of air from the chest wall, diaphragm, mediastinum or esophagus
  • Gas-forming organisms in empyema
11
Q

Pneumothorax

Clinical Symptoms

A
  • Chest pain, dyspnea
  • Absent breath sounds on auscultation
  • Tympanitic percussion (hyper-resonance)
  • Contralateral deviation of the trachea on CXR
  • Compression and collapse of lung parenchyma with atelectasis
  • Marked respiratory distress
12
Q

What are the clinical signs and causes of a spontaneous pneumothorax?

A
  • Encountered in young individuals secondary to rupture of small apical lung blebs or bullas
  • Trachea is deviated to the ipsilateral side
    • usually subsides spontaneously
  • Causes:
    • Idiopathic (unknown cause)
    • Bronchopleural fistula
    • Bullous emphysema
13
Q

What are the clinical signs and causes of a tension pneumothorax?

A
  • Due to penetrating trauma to the lungs
    • Produces increased pleural cavity pressure with compression and atelectasis
    • Flap-like pleural defect acts like a valve allowing air in but not out
  • Sudden onset of respiratory distress (medical emergency)
  • Trachea deviated to contralateral side of pneumothorax
14
Q

Example of Pleural Neoplasms:

  1. Benign:
  2. Malignant:
A
  1. Benign:
    • Solitary fibrous tumor (pleural fibroma)
  2. Malignant:
    • Metastases from other organs
    • Malignant mesothelioma
15
Q
  • Describe a solitary fibrous tumor:
  • What is it associated with?
A
  • Polypoid, well-circumscribed, pedunculated
  • Composed of fibroblasts with abundant collagenized stroma
  • Benign tumor, cured by simple excision
  • Mostly asymptomatic and discovered incidentally on chest X-rays
  • Associated with hypoglycemia and clubbing of the fingers
16
Q
  • Define malignant mesothelioma:
  • What age group is it most common in?
A
  • Neoplastic proliferation of mesothelial cells lining serosal surfaces
    • Affects 15-20 persons per million/per year in the general population
  • Most common in adults over 50
17
Q

What are etiologies of malignant mesothelioma?

A
  • Asbestos exposure
  • Idiopathic (up to 50% of cases)
  • Radiation
  • Chronic inflammation
  • Viral infections (SV40 simian virus in old polio vaccines)
18
Q

What is the incidence of asbestos-related mesothelioma?

A
  • Epidemiologic studies (coastal areas of US and GB and mining areas in Canada and So. Africa)
  • Lifetime risk for developing mesothelioma is up to 10% in patients with a history of heavy exposure
  • Long latency period (20-40 years)
  • Occupational exposure: millworkers, roofing materials, textiles, insulation, shipyard workers
19
Q

Abestos-related Mesothelioma:

Clinical Symptoms

A
  • Insidious, slow growing neoplasm
  • Recurrent pleural effusions
  • Chest pain and dyspnea in more advanced stages
  • Only 20% of patients have pulmonary fibrosis (asbestosis)
  • Fatal malignancy; median survival 18 months
20
Q

How does mesothelioma appear histologically?

A
  • Tumor characteristically spreads along mesothelial surfaces
  • Composed of bland-appearing cuboidal cells that resemble normal mesothelial cells (well-differentiated neoplasm)
  • Very difficult for pathologist to distinguish mesothelioma from metastatic carcinoma to the pleura
  • Can also involve other serosal surfaces like peritoneum, tunica vaginalis and pericardium
21
Q

________ ______ are more common than primary malignancies in the pleura

A

Metastatic tumors are more common than primary malignancies in the pleura

22
Q

Describe how metastatic tumors spread:

A
  • Lung is the most frequent source of metastases to the pleura
    • other tumors include breast and ovarian cancer, pancreas, kidney
  • Spread is by blood, lymphatics or direct extension
  • Metastases are often multiple and bilateral
23
Q

What are the mediastinal compartments?

A
  1. anterior/superior
  2. medial
  3. posterior
24
Q

What are the different types of mediastinal inflammation?

A
  1. Acute mediastinitis
    • Complication of conditions affecting neighboring organs
    • esophageal perforation, perforation of lung abscess, sternal osteomyelitis, etc
  2. Granulomatous mediastinitis
    • Chronic disorder secondary to fungal or mycobacterial infection
  3. Idiopathic sclerosing mediastinitis
    • Unknown etiology
25
Q

What causes granulomatous mediastinitis?

A
  1. Histoplasmosis
  2. Tuberculosis
  3. Cryptococcosis
  4. Atypical mycobacteria
  5. Aspergillosis
26
Q

Tumors of the Mediastinum

Anterior/Superior

A
  1. Metastatic tumors
  2. Thymoma, thymic CA
  3. Lymphomas
  4. Germ cell tumors
  5. Sarcomas
  6. Congenital thymic cysts
27
Q

Tumors of the Mediastinum

Medial

A
  1. Metastatic tumors
  2. Pericardial cyst
  3. Bronchogenic cyst
  4. Lymphomas
28
Q

Tumors of the Mediastinum

Posterior

A

Neurogenic tumors

  1. Schwannoma
  2. Neurofibroma
  3. Ganglioneuroma
  4. Neuroblastoma
29
Q

Congenital Cysts

  • Clinical Presentation:
A
  • Usually unilocular
  • Children aged 5 to 15 years
  • Lined by simple cuboidal epithelium
  • May be filled with serous fluid
30
Q

What is thymic lymphoid follicular hyperplasia associated with?

A

myasthenia gravis and other autoimmune disorders

31
Q

Myasthenia Gravis

  • Associated with:
  • Pathogenesis:
  • Symptoms:
A
  • May be associated with thymic lesions
    • Thymic hyperplasia
    • Thymoma (30-40% of patients with thymoma develop MG)
    • Thymic carcinoma
  • Auto-antibodies form to acetylcholine receptor in neuromuscular junction
    • Autosensitization to AChR is initiated in the thymus due to defective confrontation of ACh-secreting thymic myoid cells with T-lymphocytes
  • Symptoms: weakness, fatigability, ptosis, diplopia
32
Q

What is a thymoma?

  • What is its clinical presentation?
  • How does it appear histologically?
A
  • Neoplastic proliferation of thymic epithelial cells
    • Usually contains abundant immature T-lymphocytes (non-neoplastic)
  • Frequently associated with myasthenia gravis and other paraneoplastic syndromes
  • May be composed of spindle cells or round epithelioid cells
    • type A (spindle cells)
    • type B (round cells)
    • type AB (mixture of both)
  • Slow-growing tumor that may recur but rarely metastasizes
33
Q

Thymoma

  • Symptoms:
  • Paraneoplastic syndromes:
A
  • Symptoms:
    • Asymptomatic in 30% of patients
    • Cough, dyspnea, chest pain
    • Superior vena cava syndrome
      • obscures or obstructs the SVC
  • Paraneoplastic syndromes:
    • Myasthenia gravis
    • Pure red cell aplasia
    • Hypogammaglobulinemia
    • Agranulocytosis; white blood cell aplasia
    • Polymyositis; SLE
    • Pemphigus vulgaris, disseminated herpes
34
Q

What is the clinical behavior of a thymoma?

A
  • Depends on the status of the capsule
    • Encapsulated tumors ⇒ cured by complete surgical excision
    • Invasive tumors ⇒ tend to recur repeatedly and may eventually metastasize
  • Recurrent tumors may progress to thymic carcinoma
35
Q
  • What is the histology of thymic carcinoma?
  • How is a diagnosis made?
A
  • Resemble other types of carcinoma occurring in other organs (squamous, small cell, adenocarcinoma, etc)
  • Diagnosis of exclusion (i.e., there are no specific features that permit definite histologic diagnosis)