Disseminated cryptococcosis: a diagnostic challenge in an immunocompromised patient

Background: Cryptococcosis is an opportunistic fungal infection that causes disseminated disease in immunocompromised patients. Peritoneal involvement is rare and diagnostically challenging. Case report: A 76-year-old man with Crohn's disease on infliximab and previously treated latent tuberculosis was admitted with constitutional symptoms and abdominal distention evolving over 5 months. Ultrasound revealed bilateral pleural effusion and ascites. Initial hypotheses-peritoneal carcinomatosis and tuberculosis-were excluded through computed tomography scan, laboratory tests, and exploratory laparoscopy with biopsy, which showed necrotizing granulomatous peritonitis. Disseminated cryptococcosis was confirmed by India ink staining, cultures from peritoneal and pleural fluids, and serum cryptococcal antigen. Cerebrospinal fluid analysis and ophthalmological evaluation excluded central nervous system and ocular involvement. Treatment with liposomal amphotericin B and flucytosine led to clinical improvement. Conclusion: This case highlights the importance of considering cryptococcosis in the differential diagnosis of polyserositis in immunocompromised patients. Early diagnosis and antifungal therapy improve outcomes. LEARNING POINTS: Disseminated cryptococcosis, although rare, should be considered in the differential diagnosis of polyserositis and necrotizing granulomatous peritonitis in immunocompromised patients.Cryptococcus can closely mimic tuberculosis or peritoneal carcinomatosis; negative mycobacterial studies should prompt fungal investigations, including cryptococcal antigen testing.Early diagnosis and timely initiation of antifungal therapy are crucial to reduce morbidity and mortality, with treatment tailored to comorbidities such as renal dysfunction.