Pancreatic Head Mass: A Rare Manifestation of Granulomatosis With Polyangiitis.

Granulomatosis with polyangiitis may rarely present as an inflammatory pancreatic mass and mimic pancreatic cancer. We report a 73-year-old man who presented with fever and weight loss. Computed tomography imaging demonstrated a mass in the pancreatic head along with multiple cavitary pulmonary nodules. Our differential included metastatic pancreatic cancer vs an autoimmune process. Positive cytoplasmic antineutrophil cytoplasmic antibodies coupled with the lung biopsy findings established the diagnosis of granulomatosis with polyangiitis, a very rare cause of pancreatic masses. After completion of immunosuppressive therapy, magnetic resonance imaging demonstrated no evidence of a pancreatic mass. More studies are required to establish the management of these masses.