B72-17 A Case of Unexpected Cryptococcal Pleuritis

Abstract Introduction Cryptococcosis is an opportunistic fungal infection caused by Cryptococcus neoformans or C. gattii, typically affecting the lungs or central nervous system (CNS). Pleural involvement is rare and may be overlooked. While most cases occur in immunocompromised hosts, infection can also arise in patients with chronic illnesses such as diabetes or end-stage renal disease (ESRD). Case Description A 60-year-old woman with hypertension, coronary artery disease, systolic heart failure (ejection fraction 20-25%), ESRD, diabetes, schizophrenia, and cocaine use presented with chest pain after missing dialysis. She was volume overloaded with elevated troponin, consistent with type II non-ST-elevation myocardial infarction. Chest CT angiography showed a large right pleural effusion (Figure 1). Initial thoracentesis revealed transudative fluid, attributed to heart failure and renal disease. She improved with dialysis; however, pleural fluid cultures unexpectedly grew Cryptococcus. Repeat thoracentesis again demonstrated transudative fluid with a second positive culture. Serum cryptococcal antigen was initially positive (1:5). HIV, RPR, hepatitis C, gonorrhea, and chlamydia tests were negative. Blood and urine cultures were negative; head CT showed no CNS lesions. Lumbar puncture and bronchoscopy with BAL were unremarkable. Skin biopsy of pruritic papules revealed a non-infectious process. Despite transudative characteristics, repeated positive cultures and antigen supported cryptococcosis with pleural involvement. She was treated with amphotericin B and flucytosine, followed by fluconazole. Discussion Cryptococcal pleural infection is rare and typically associated with profound immunosuppression, most often in HIV-positive individuals. However, disseminated cryptococcosis with isolated pleural involvement can occur in patients without overt immunodeficiency. In this case, cumulative comorbidities (ESRD, diabetes, heart failure, and chronic cocaine use) likely contributed to functional immunosuppression, increasing susceptibility to opportunistic fungal disease. A notable diagnostic challenge was the discrepancy between pleural fluid analysis and culture results. The effusion repeatedly met Light’s criteria for transudate, classically considered non-infectious, yet serial cultures grew Cryptococcus, and serum antigen was intermittently positive. Transudative effusions in medically vulnerable patients should not exclude infection. Lack of pulmonary parenchymal or CNS disease and negative fungal studies from CSF, BAL, and skin supported isolated pleural cryptococcosis. A high index of suspicion is warranted in complex patients with atypical presentations. When initial testing is inconclusive, repeat sampling and fungal diagnostics are critical. Early antifungal therapy may be appropriate when suspicion persists, regardless of pleural fluid classification. This abstract is funded by: None