A 32-year-old woman presents with a 6-week history of fever, erythema nodosum on her shins, and migratory polyarthralgia. Chest X-ray shows bilateral hilar lymphadenopathy with prominent **right paratracheal lymphadenopathy** (marked **C**). Transbronchial lung biopsy reveals non-caseating epithelioid granulomas. Which of the following best describes the pathological hallmark that confirms the diagnosis of sarcoidosis in this patient?
A. Granulomatous inflammation with fibrinoid necrosis and immune complex deposition
B. Caseating granulomas with central caseous necrosis and acid-fast bacilli
C. Non-caseating (non-necrotizing) epithelioid granulomas without central necrosis
D. Suppurative granulomas with neutrophilic infiltration and abscess formation
Explanation
Why "Non-caseating (non-necrotizing) epithelioid granulomas without central necrosis" is right
Sarcoidosis is defined as a multisystem granulomatous disease of unknown etiology characterized by non-caseating epithelioid granulomas. The presence of non-caseating granulomas on histology (typically obtained via EBUS-FNA of mediastinal nodes or transbronchial lung biopsy) is a cardinal diagnostic criterion. The right paratracheal lymphadenopathy marked C, combined with bilateral hilar lymphadenopathy, forms the classic "1-2-3 sign" or Garland triad of Stage 1 sarcoidosis. The absence of central necrosis (caseation) distinguishes sarcoidosis from tuberculosis and other infectious granulomatous diseases. (ATS/ERS/WASOG Sarcoidosis Guidelines 2020)
Why each distractor is wrong
Caseating granulomas with central caseous necrosis and acid-fast bacilli: This is the pathological hallmark of tuberculosis, not sarcoidosis. TB presents with caseating (necrotizing) granulomas, often with acid-fast bacilli visible on special stains. Sarcoidosis is explicitly non-caseating.
Suppurative granulomas with neutrophilic infiltration and abscess formation: This pattern is seen in bacterial infections (e.g., cat-scratch disease, tularemia) and some fungal infections, not sarcoidosis. Sarcoid granulomas are epithelioid and non-suppurative.
Granulomatous inflammation with fibrinoid necrosis and immune complex deposition: Fibrinoid necrosis is characteristic of hypersensitivity pneumonitis and some vasculitic conditions, not sarcoidosis. Sarcoid granulomas do not show fibrinoid necrosis.
High-YieldNEET PG
Sarcoidosis = non-caseating granulomas; TB = caseating granulomas. This distinction is the cornerstone of differential diagnosis and is essential for NEET-PG.
ATS/ERS/WASOG Sarcoidosis Guidelines 2020
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