Perspective Chapter: Necrotizing Sarcoid Granulomatosis

Abstract

Necrotizing sarcoid granulomatosis (NSG) is a rare pulmonary granulomatous disorder characterised by a histopathological triad of sarcoid-like non-caseating granulomas, necrotizing granulomatous vasculitis, and variable necrosis. While its classification as a distinct entity versus a variant of nodular sarcoidosis remains controversial, NSG is clinically distinguished from classic sarcoidosis by the frequent absence of significant hilar lymphadenopathy and typically normal serum angiotensin-converting enzyme (ACE) levels. The condition predominantly affects middle-aged women and presents radiologically with bilateral pulmonary nodules or masses, frequently displaying the “galaxy sign” or “cluster sign.” This review details the epidemiology, clinical features, and diagnostic requirements of NSG, emphasising the importance of histopathological confirmation to exclude malignancy and infectious aetiologies. Finally, therapeutic approaches are examined; the prognosis is generally benign, with 30–40% of cases resolving spontaneously and symptomatic patients showing excellent response to corticosteroid therapy, although long-term surveillance is advised due to the potential for evolution into systemic sarcoidosis.