J. Messler 1 , V. Nunez 1 , T. Jacobson 1 ; 1 Emory University, Atlanta, GA LEARNING OBJECTIVES: 1. Learn the differential diagnosis of pulmonary cavities in HIV patients. 2. Recognize the importance of bronchoscopy for diagnosis. 3. Recognize the various pulmonary manifestations of cryptococcus. CASE INFORMATION: A 41yo homeless man presents to the walk-in clinic with a chief complaint of cough. He complains of blood-tinged sputum for two months, worsening over the past three weeks. He denies fever or chills but reports night sweats, dizziness, decreased appetite, and weight loss. Except for an episode of``bronchitis'' treated 2 months earlier, his past medical history is unremarkable. A former intravenous drug user, he has lived in and out of shelters for three years. A recent PPD was negative. He admits to multiple, unprotected bisexual contacts in the past year. He has never been tested for HIV. On admission, his temperature is 39.1C, pulse 98, respirations 16, and blood pressure 100/60, sitting and lying down. Significant findings on his exam include bitemporal wasting, pale conjunctiva and oral thrush. Chest x-ray on admission reveals a 3cm cavity in the right posterior upper lobe. His PPD is negative and sputum cultures for AFB are negative. He tests positive for HIV with a CD-4 count of 6mm3. Bronchoscopic washings grow budding yeast. Serum cryptococcal antigen returns positive at a titer of greater than 1:512. The opening pressure from the lumbar puncture is normal. Cerebrospinal fluid (CSF) analysis contains 4 WBC, glucose 40, and protein 50. CSF yields a positive india ink stain and CSF cryptococcal antigen titer is positive. Subsequently, he begins therapy for cryptococcal pneumonia and cryptococcal meningitis. DISCUSSION: In HIV patients, the differential diagnosis for pulmonary cavities is extensive. The most common etiology is tuberculosis. However, as the CD-4 count falls below 200mm3, tuberculous cavities decrease in prevalence. Various other etiologies include atypical pneumocystis presentation, toxoplasmosis, invasive fungal infections, bacterial infections, and neoplasms including Kaposi's sarcoma. Sputum samples are a start to diagnosis, but bronchoalveolar lavage or biopsy would likely be required to obtain a definitive diagnosis for a cavitary process. A cavitary lesion involving cryptococcosis is a rare occurrence. Usual radiographic presentations for pulmonary cryptococcosis include interstitial infiltrates or pleural effusions. Additionally, there is no typical clinical picture. Interestingly, although the majority of cryptococcal patients are initially diagnosed with disseminated CNS disease, the pulmonary complaints of cryptococcosis often precede the diagnosis of meningitis by months. The variety of clinical and radiographic presentation underscore the need for definitive diagnosis, especially in the patient with clinically silent cryptococcal meningitis. 