CASE PRESENTATION: A 47 year-old woman with past medical history of Asthma, sinusitis, migraine headache; presented with intermittent epigastric pain, nausea and vomiting. Examination was significant for right upper quadrant pain and guarding. Blood work was consistent with WBC count of 17000 with 32% eosinophil. Abdominal U/S demonstrated thickening of gallbladder with sludge but no stone, endoscopy showed thickening of duodenal bulb along with duodenal polyp, HIDA scan showed biliary dyskinesia EF 18%. CT scan of the abdomen showed 2 mm hypodensity within the right hepatic lobe along with haziness of the porta hepatis. Patient subsequently had laparoscopic cholecystectomy. Biopsy of the liver and resected gallbladder were consistent with necrotizing eosinophilic vasculitis which fills the criteria of CSS. P-ANCA titers and IgE level were both elevated. IV Steroid was started with significant symptoms improvement in 24 hours. Patient was discharged home on oral prednisone and instructed to follow up with a rheumatologist.