Ascites in a young male: idiopathic FIP1L1-PDGFRA-negative hypereosinophilic syndrome

INTRODUCTION: Idiopathic hypereosinophilic syndrome is defined as persistently elevated peripheral blood absolute eosinophil count of more than 1.5 × 109/L for at least six months with no obvious secondary cause. CASE PRESENTATION: We report the case of a 26-year-old gentleman of Malay ethnicity who presented to the medical department with a three-week history of abdominal distension associated with dyspepsia and epigastric pain. Physical examination revealed ascites. The complete blood count portrayed peripheral leucocytosis with eosinophilia of 8.84 × 109/L. Parasitic serology was negative. Paracentesis analysis showed exudative ascites with an absolute eosinophil count of 8 × 109/L. He was referred to the haematology department. He was noticed to have bilateral tonsillitis and pruritic skin rash at the legs. There were no palpable lymph nodes or organomegaly. A peripheral blood film showed 44% eosinophils with no excess blasts. Clonal eosinophilic fusion studies did not detect FIP1L1-PDGFRA mutation. JAK2 V617F and BCR-ABL1 mutations were undetected. Serum B12 and tryptase levels were normal. A whole-body computed tomography imaging showed bowel wall thickening at the duodenum, jejunum, ileum, rectosigmoid and splenic flexure. Sections of fragments taken from the endoscopy showed features of eosinophilic gastritis and colitis on histology. Bone marrow biopsy depicted marked eosinophilia. He was started on oral imatinib mesylate 200 mg daily and oral prednisolone 0.5 mg/kg daily which was tapered based on response. He achieved complete remission and is now asymptomatic. CONCLUSION: The diagnosis of hypereosinophilic syndrome should be considered in a patient with unexplained ascites. Secondary sinister causes such as malignancy should always be excluded.