The type of necrosis seen in tuberculosis is

KGMU 2024

Pathology & Genetics

Easy

Appeared in: KGMU 2024

Explanation

Caseous necrosis is the hallmark pathological feature of tuberculosis.
The term 'caseous' refers to the cheese-like, friable, and yellowish-white gross appearance of the necrotic tissue.
It is a unique form of cell death that combines features of both coagulative and liquefactive necrosis, where tissue architecture is completely obliterated.
Microscopically, it appears as amorphous, granular debris surrounded by a characteristic granulomatous inflammation (Langhans giant cells, epithelioid macrophages).

Option A: Coagulative necrosis is incorrect because it is characterized by the preservation of cellular outlines, which are lost in the necrosis seen in tuberculosis. It is typically caused by ischemia in solid organs like the heart and kidney.
Option B: Liquefactive necrosis is incorrect because it results in the transformation of tissue into a liquid, viscous mass. This is different from the semi-solid, 'cheesy' texture of caseous necrosis.
Option D: Gangrenous necrosis is a clinical term describing large-scale tissue death (e.g., a limb) due to ischemia, not a distinct microscopic pattern of necrosis. The underlying process is usually coagulative necrosis.

Visual 1: Microscopic Image - A slide showing caseous necrosis with its characteristic amorphous, eosinophilic center and surrounding granulomatous inflammation, including epithelioid cells and Langhans giant cells. This helps visualize the key features of TB-related necrosis.
Visual 2: Gross Image - A photograph of a lung or lymph node specimen showing the gross, 'cheese-like' appearance of caseous necrosis.
Visual 3: Comparison Chart - An infographic comparing the microscopic and gross features of coagulative, liquefactive, caseous, and fat necrosis.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Types of cellular necrosis and their association with specific diseases as background academic context rather than a clinical decision trigger.
Understanding that caseous necrosis is a sign of tuberculosis is crucial for diagnosis. When a pathologist sees this on a biopsy, it raises a high suspicion for TB, prompting further specific tests like acid-fast staining or molecular diagnostics.
The presence of caseous necrosis within a lung lesion (a 'Ghon focus') is a key component in diagnosing primary tuberculosis.
What if? If a lung biopsy showed coagulative necrosis instead of caseous necrosis, the primary diagnosis would shift away from tuberculosis towards conditions like pulmonary infarction (a blood clot in the lung) or vasculitis.

How to Approach the Question

First, identify the key terms in the question: 'necrosis' and 'tuberculosis'.
The question asks for a specific type of necrosis associated with a specific disease.
This is a direct recall question based on foundational pathology knowledge.
Recall the different types of necrosis and their classic associations.
Coagulative necrosis is linked to ischemia (e.g., heart attack).
Liquefactive necrosis is linked to brain infarcts and abscesses.

Concept Tested & Keywords

Concept Tested: Types of cellular necrosis and their association with specific diseases.
Stem keywords: necrosis, tuberculosis
Lead-in keywords: type of

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