S5165 Unmasking Eosinophilic Ascites: A Rare Case of Omental Coccidioidomycosis

Introduction: Coccidioidomycosis is a fungal infection endemic to desert regions such as the southwestern United States. Most infected patients are asymptomatic or have respiratory symptoms. Dissemination occurs in <1% of cases. Common sites include skin, joints, and central nervous system, while peritoneal and omental involvement is extremely rare. Hematogenous spread from pulmonary infection is most common, though direct seeding via infected sputum is possible. We describe a case of a young man presenting with eosinophilia and ascites, ultimately diagnosed with omental coccidioidomycosis. Case Description/Methods: A 31-year-old Haitian man, who immigrated 6 months prior, presented with progressive abdominal pain and distention for 3 weeks. He denied fevers, night sweats, weight loss, or respiratory symptoms. He was afebrile, hemodynamically stable, and had ascites without other stigmata of chronic liver disease. Labs were notable for eosinophilia (14.9%, absolute 800/uL); liver function and albumin (4 g/dL) were normal. Computed tomography (CT) showed large ascites, omental nodularity, mesenteric inflammation with lymphadenopathy, and a right lower lobe pulmonary nodule. Paracentesis revealed inflammatory ascitic fluid (white blood cell 5859/mm³) with eosinophils and histiocytes; cytology and cultures were negative. Extensive infectious, autoimmune, parasitic workup, and endoscopy with biopsies were unrevealing. Though coccidioides IgG and CF titer were positive (1:64), peritoneal cocci serologies were negative. Due to refractory ascites, exploratory laparotomy revealed miliary omental and peritoneal nodules. Biopsies showed non-necrotizing granulomas with fungal spherules consistent with Coccidioides immitis. He was discharged on high-dose fluconazole and at 6 weeks follow up his ascites resolved and did not recur. Discussion: This case highlights an extremely rare presentation of disseminated coccidioidomycosis with omental involvement manifesting as eosinophilic ascites. Diagnosis was delayed due to absent respiratory symptoms and negative peritoneal studies. Omental biopsy ultimately unveiled the diagnosis. Clinicians should maintain high suspicion for disseminated coccidioidomycosis in endemic areas and unexplained eosinophilia. Early recognition and antifungal therapy can result in full clinical resolution.