Follow-up cranial CT scan carried out one day later revealed the persistence of the mass lesions and the progression of hydrocephalus. Another chest roentgenogram showed diffuse opacity throughout both lungs with a diffuse brochopneumonic appearance.

Despite the institution of intravenous amphotericin B, the patient continued to deteriorate neurologically and died two days after beginning therapy. The autopsy showed diffuse Cryptococcus pneumonia and multiple intracerebral lesions with numerous fungal cells. Cultures revealed C. gattii.

DISCUSSION

Cryptococcus gattii is emerging as a primary human and animal pathogen. The principal source of the organism is wood debris in hollows, particularly that of eucalyptus⁸ and is prevalent in the tropical and subtropical areas and rare in cold climates⁵. In contrast, C. neoformans is widespread in the environment, especially in areas burdened with bird excreta, and has a worldwide distribution. After gaining entry through the respiratory tract, both have trophism for the central nervous system (CNS); patients infected by C. gattii are more likely to evidence focal pulmonary and CNS mass^2,7,9. Both inhibition of polymorphonuclear leukocyte migration to the site of infection³ and inhibition of neutrophil function¹¹ by products of C. gattii may promote survival of extracellular organisms, and local multiplication to form cryptococcomas.

Infection due to C. gattii can pose a diagnostic challenge to clinicians. This case vividly illustrates the fact that, pulmonary cryptococcosis with mass-like lesion with associated cerebral infection, exhibit radiologic features that mimic those of lung cancer metastatic to the CNS. Isolated pulmonary cryptococcosis simulate pulmonary cancer particularly when it appears as an apical mass, including with a typical Pancoast's syndrome⁶. In these cases, cryptococcal antigen testing by latex agglutination, a rapid test with high specificity, would be useful in the differential diagnosis.

Fungemia¹⁰ and funguria⁴ by C. gattii is highly unusual. On the other hand, infections due to C. neoformans can be isolated from blood up to 63% of patients⁹. Positive blood culture is a sign of very poor prognosis and most patients had a high tissue burden of organisms in the lung and CNS¹, like our patient.

In summary, C. gattii must be included in the differential diagnosis of pulmonary and brain masses. Furthermore, with fungal cultures, smears, and serologic test systemic cryptococcosis will be diagnosed sooner, leading to earlier treatment which may be life-saving.