Granulomatosis polyangiitis (GPA) is a systemic, necrotizing, granulomatous, antineutrophil cytoplasmic antibody (ANCA) -associated vasculitis that affects small and medium arteries, mainly affecting the upper and lower respiratory tract and the kidneys. It is usually seen over 40 years old. Diagnosis is based on clinical findings, cytoplasmic- C-ANCA positivity and histological findings. Here we report a case of 21-year-old patient who presented with petechial purpuric lesions, abdominal pain, large joint arthritis and hematuria- proteinuria and to whom we started treatment for Henoch-Shonlein Purpura. But a chest imaging showed mass lesion and our final diagnosis was atypical GPA after excluding malignancy, cryoglobulinemia and ANCA related vasculitis in differantial diagnosis.