Where is Onion skin fibrosis seen?

AIIMS Raipur NO - 2019 (Shift-2)

Pathology & Genetics

Easy

Appeared in: AIIMS Raipur NO - 2019 (Shift-2)

Explanation

Primary Sclerosing Cholangitis (PSC) is the correct answer as it is defined by the characteristic histological finding of 'onion skin' fibrosis.
This pattern consists of concentric layers of fibrous tissue deposited around the intrahepatic bile ducts due to chronic inflammation.
This periductal fibrosis leads to the narrowing and eventual obliteration of the bile ducts, causing strictures and cholestasis.
On imaging (MRCP/ERCP), this process results in a 'beaded' appearance of the bile ducts, with alternating areas of stricture and dilation.

Option A: Primary Biliary Cholangitis (PBC) is characterized by a 'florid duct lesion,' which involves granulomatous destruction of the bile ducts, not the concentric fibrosis seen in PSC.
Option C: Biliary atresia is a condition of newborns involving the fibrotic obliteration of extrahepatic bile ducts. It does not present with the classic onion skin pattern.
Option D: Acute cholecystitis is the acute inflammation of the gallbladder wall, typically due to gallstone obstruction. Its histology shows edema and neutrophilic infiltrate, not a chronic fibrotic process like onion-skinning.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Histopathological features of hepatobiliary diseases as background academic context rather than a clinical decision trigger.
Recognizing the association between onion skin fibrosis and PSC is crucial for diagnosis and management, as PSC carries a significant risk of progressing to cirrhosis and cholangiocarcinoma (bile duct cancer).
Nurses should be aware of the strong association (around 70%) between PSC and inflammatory bowel disease (IBD), particularly ulcerative colitis. Patients with IBD presenting with elevated liver enzymes (especially alkaline phosphatase) should be evaluated for PSC.
Patient education is vital, focusing on symptom management (e.g., pruritus), monitoring for complications like cholangitis (fever, jaundice, abdominal pain), and the need for regular cancer surveillance.

How to Approach the Question

First, identify the key term in the question, which is 'Onion skin fibrosis'.
Recognize this as a specific, pathognomonic histological finding associated with a particular disease.
Systematically review the options provided, which are all diseases of the liver and biliary system.
Recall or deduce the classic histopathology for each condition.
Match 'Onion skin fibrosis' to Primary Sclerosing Cholangitis (PSC).
Confirm the choice by mentally excluding the other options: PBC (florid duct lesion), Biliary atresia (duct obliteration in neonates), and Acute cholecystitis (acute inflammation).

Concept Tested & Keywords

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E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed pp. 860-862, 859-861