A case of multiple cavities on chest film with high titer of serum cryptococcal antigen

Abstract

A 26-year-old man admitted to Nishinomiya Municipal Hospital for further evaluation for abnormal shadows on the chest film in a mass examination. He had no subjective complaints; for example, cough, sputum or dyspnea. His past history and physical examinations yielded no significant findings. The chest film revealed the multiple cavities accompanied with a little infiltration throughout several lobes bilaterally. The inflammatory reactions; such as, CRP and ESR, were all intact, but the titer of the serum cryptococcal antigen was high. He was not immunocompromised. Although bronchoscopy and transbronchial lung biopsy were performed twice during admission, they revealed no pathogenic findings both bacteriologically and histologically. The elevation of the serum cryptococcal antigen titer suggested that this disease is the primary pulmonary cryptococcosis. The titer decreased with spontaneous disappearance of the abnormal shadows on the chest film. This test has a sensitivity of 90% for cryptococcal infection, but in rheumatoid arthritis, a small percentage of false positive results have been reported. Therefore, if the rheumatoid factor is eliminated, the test is more specific for cryptococcal infection. On the other hand, some authors have reported the false positive results in Trichosporon beigelii infection by this method. But this disease is negligible for its frequency in clinical features in our country. We emphasized that this non-invasive test is more useful for the diagnosis of the primary pulmonary cryptococcosis.