Pathology of Pleura

Mesothelial reactions to damage

• Reaction to irritation:

  • cell swelling,

  • desquamation

• Unusual recovery:

  • Centripetal proliferation (curved around the centre)

  • Recombination of desquamated cells

  • Formation of new mesothelial cells from sub-mesothelial fibroblasts

• May cause morphological diagnostic problems

Mesothelial healing

Inflammation of the pleura

• Fibrinous pleurisy

• Acute purulent pleurisy

• Chronic purulent pleurisy / pleural empyema

• Chronic granulomatous inflammation:

  • Tuberculosis

  • Sarcoidosis

  • Foreign body type granulomas

Acute pleurisy

• Hyperaemia

• Fibrinous pleurisy with pleural effusion

• Serofibrinous pleurisy: Friction is reduced when exudation begins

• Purulent pleurisy

• Pleural empyema

Pleura empyema

Collection of pus in the pleural space, most commonly isolated between connective tissue adhesions

Cause - bacterial infection

Contributing factors:

• Diabetes

• Alcoholism

• Chronic lung diseases (bronchiectasis, cancer)

• Immunosuppression

• Surgical manipulations

Tuberculosis in pleural tissues

Pleural damage is common in patients with tuberculosis

May be

• Isolated tuberculous pleurisy

• In connection with active pulmonary tuberculosis

• Tuberculosis empyema if tbc cavernous erodes on pleural space

Eosinophilic pleuritis

Eosinophil pleurisy:

• pneumothorax

  • Eosinophilic infiltrate penetrates tissue to a depth of <3 mm. Mesothelium is grossly hyperplastic.

• eosinophil pneumonia

• eosinophilic granuloma

• malignancy

Pleural fibrosis

• If fibrosis develops in the pleura, the amount of connective tissue in the pleura increases. The pleura thickens in the affected areas

• Pleural fibrosis can be caused by:

  • Acute inflammation, prolonged

  • Pleural tbc

  • Uncommon pathologies

    • Asbestos-induced inclusions

    • Blesovsky's disease

Pleural Tumours

The most common primary pleural tumours:

• Malignant mesothelioma

• Solitary Fibrotic Pleural Tumour (SFPT)

Mesothelioma s. diffuse malignant mesothelioma

Definition – malignant tumour that develops from mesothelial cells

Typical age and gender:

• 6th decade of life

• Rarely for young people

• More common in men

Fatality 100%

90% of cases are caused by asbestos

Growth and spread of mesothelioma

1. Diffusely spreads over the surface of the serous sheath: first small nodules, which then fuse to form a sheath

2. The lungs are compressed

3. Exudation to the pleural space

4. Can grow into pulmonary parenchyma and metastasize to laryngeal and mediastinal LM and further

5. Possible widening of the waistline to the healthy side

6. It grows in the adipose tissue and musculature of the thoracic wall. Typical implantation at sites of puncture, biopsy, or thoracocentesis

Immunophenotype: Contains calretinin and HBME-1: markers specific for mesothelium

Solitary fibrous tumour (SFT)

• CD34-positive fibroblast tumour

• Characteristic of the pleura but possible in any localization, e.g. orbit, kidney, deep soft tissue

• Risk factors are unknown. The development of this tumour is not related to asbestos

SFT: clinical picture

• May be an accidental radiological finding

• Cough

• Pain in the chest

• Shortness of breath

• Possible hypoglycaemia due to synthesis of insulin-like growth factor in tumour cells

Localized / Solitary Fibrotic Pleural Tumour (SFPT)

• FOCAL INVASIVE GROWTH

• benign SFPT may include mesothelium not to be confused with biphasic differentiation

• benign visceral pleural SFPT can focally grow into lung tissues including alveolar epithelium

Malignant SFTP: hypercellularity and high mitotic activity

Metastatic tumours in pleura

• Most common malignancy in pleura

• In patients> 50 years, the 2nd most common cause of pleural effusion (after CHI – chronic heart insufficiency )

• Origin

  • 33% lung Ca

  • 20.9% breast Ca

  • 7.3% stomach Ca

  • ovaries Ca

• 46% of these cancers are primarily manifested by metastatic pleurisy

• lymphoma