Comprehensive Overview Of Lung Pathology Images

A comprehensive overview of lung pathology images helps in diagnosing pulmonary diseases like pneumonia, tuberculosis, lung cancer, and COPD. Examining histological slides, X-rays, and CT scans enhances understanding of disease features, aiding in accurate diagnosis and progression analysis. Essential for NEET PG and clinical medical practice.

Obstructive Lung Disease

COPD

• Emphysema (smoking) -also known as pink puffers
  • Permanent damage to airways
  • Distal to terminal bronchioles
    • Respiratory Bronchiole
    • Alveoli duct
    • Alveolar Sac
• Chronic Bronchitis (smoking), also known as blue bloaters

Emphysema 

Centriacinar Emphysema

• Most common clinically
• Smokers (upper lobe)
• The respiratory Bronchiole is affected
• The Alveoli duct and sac are saved

Panacinar Emphysema

α-antitrypsin deficiency (lower lobes)

All are damaged

Distal Acinar/ Paraseptal Emphysema

• Spontaneous pneumothorax
• The Alveoli duct and sac are damaged
• The respiratory Bronchiole is saved

Irregular Emphysema

Most common histologically

Also read: Pathology One-Liners for Medical Students

Asthma

Airway Remodelling (Chronic Asthma)

• Mucosa thickened
  • Increase in Goblet cells
  • Increase in BM thickness
  • Increase in Eosinophils in lamina propria
  • Increase in Muscularis mucosae
• Increase in submucosal glands

Bronchiectasis 

Definition

Dilation of the bronchi and bronchioles

Causes

• Genetic - Kartagener syndrome - dynein defect of CILIA: Associated with male-female infertility
• Acquired - Obstruction or sepsis

Most common - Left lower lobe

IOC - HRCT

• Tram track appearance is common
• Tram Track appearance is seen on microscopic examination in
• MPGN I - Membranoproliferative glomerulonephritis type I

Also read: A Comprehensive Overview of Central Nervous System

Restrictive Lung Diseases 

Sarcoidosis

• The reasons are not known
• Head-to-toe multi-organ disorder
• Most commonly affected - lungs
• Lymph nodes are known as potato nodes
• Involvement of glands and Mikulicz disease
• Can result in hepatitis (non-infectious)
• Skin lesions

Lofgren syndrome

• Lymphadenopathy
• Joint pain
• Fever
• Erythema Nodosum
• Granulomas
  • Non-caseating granuloma (Most common)
  • Naked granuloma (lymphocytic collar is not present)

Diagnosis

• Skin test - Kveim test
• Blood tests
  • Calcium levels are elevated
  • ACE levels increased
  • CD4 and CD8 are elevated
• Where else is the asteroid body seen?
  • In sarcoidosis, there is a giant cell, and the star is seen inside it, but in sporotrichosis, it is outside. (extracellular)

Also read: Pathology of Brain Tumors: Types, Grading, and Diagnosis

Asbestosis

• Pleural nodule (Asbestos / Ferruginous bodies) - dumbbell-shaped
  • Iron is deposited here
  • Prussian blue/Perl's stain
• Most common cancer - Adenocarcinoma
• Most specific cancer - Mesothelioma

Dumbbells in pathology

Lungs

Asbestos Body 

Radiology Schwannoma - spine

Urine Crystal

Calcium Oxalate Monohydrate (Mnemonic: Mona is dumb)

Microbiology: Pox virus DNA

Also read: Important Pathology Questions on Cell Injury – MCQs & Key Concepts

Lung Tumors

• Most common Benign lung tumor: Pulmonary Hamartoma
  • Coin Lesion
  • Popcorn calcification

Lung Carcinoma

Most common: Metastasis

Squamous Cell Carcinoma (Keratin pearls)

• IHC markers: p40 (best), p63
• Paraneoplastic syndrome: Hypercalcemia

Adenocarcinoma (Glands)

• IHC markers: NAPSIN A, MUC1, TTF 1
• Paraneoplastic syndrome: Migratory Thrombophlebitis (Also known as the Trousseau phenomenon)

Small Cell Carcinoma

• Most Aggressive Lung Cancer.
• Azzopardi effect (Blue blood vessels)

• IHC
  • Synaptophysin
  • Chromogranin
  • Bombesin
  • CD56, CD57, NSE
• Salt and pepper chromatin

• Neurosecretory Granules in an Electron Microscope

Also read: Plasma Cell Dyscrasia & Flow Cytometry in Hematology

Q. Nuclear marker for neuroendocrine tumor?

Answer: INSM 1

• Neuroendocrine tumor in the lung – Small cell carcinoma
• Nuclear marker—insulinoma-associated protein 1 (INSM 1)
  • Mnemonic: IN ® Intra nuclear
  • PNS
    • SIADH (most common one)
    • Cushing
    • Lambert Eaton syndrome

Pleura Mesothelioma

• Asbestosis
• Marker - Calretinin positive
• Long microvilli on electron microscopy

Adenocarcinoma

Asbestosis

Non-branching microvilli

Q. Which of these is used as a marker in mesothelioma?

1. Calretinin
2. TTF - I
3. CK - 8/9
4. Glypican

Q. What is the marker of small cell cancer of the lung?

1. Chromogranin
2. Cytokeratin
3. Desmin
4. Vimentin

Also read: Comprehensive Overview Of Lung Pathology Images

Download the PrepLadder app now and unlock a 24-hour FREE trial of premium high-yield content. Access Video Lectures, digital notes, QBank, and Mock Tests for FREE to ace your NEET PG preparation. Elevate your study experience and gear up for success. Start your journey with PrepLadder today!