Limited granulomatosis with polyangiitis presenting as an isolated lung lesion.

Granulomatosis with polyangiitis (GPA) is a systemic necrotizing vasculitis involving small and medium-sized blood vessels and granulomatous inflammation of upper and lower respiratory systems and/or renal system. In the limited form of GPA, there is no systemic involvement of disease with sparing of kidneys. The respiratory system is the commonly involved organ in limited GPA. Herein, we report the case of a 40-year-old male who was initially diagnosed as sarcoidosis clinically. Lung biopsy revealed necrotizing granulomatous angiitis. Diagnosis of GPA was made which was substantiated by antineutrophil cytoplasmic antibody (ANCA) positivity. This was a case of limited GPA with isolated lung involvement. The early diagnosis and initiation of treatment are critical for improved survival of patients with GPA. Tissue biopsy is necessary for the diagnosis of GPA.