Mimicking the mimicker: Necrotizing sarcoid granulomatosis.

Necrotizing sarcoid granulomatosis (NSG) is a rare disease that shares similarities with pulmonary vasculitides and sarcoidosis. This is a report of two cases of NSG with a review of literature. The first case is a 33-year-old black female with a one-year history of malaise and cough. Lung imaging revealed scattered pulmonary nodules. Histopathology showed multiple necrotizing granulomas without prominent neutrophilic infiltrates. The second case is a 58-year-old white female with a one-year history of fatigue, dyspnea, and ophthalmoplegia on the left eye. Imaging showed multiple pulmonary nodules. Lung biopsy was consistent with NSG. The challenge of the NSG diagnosis is to distinguish it from other mimickers. Pathology often shows necrotizing granulomatous vasculitis, distinguishing it from classical sarcoid. Laboratory markers for vasculitis like neutrophil cytoplasmic antibodies and antibodies against myeloperoxidase and proteinase 3 are negative or only low titers. NSG responds well to immune-suppression, most commonly with glucocorticoids.