[Primary pulmonary cryptococcosis confused with lung cancer by transbronchial biopsy: demonstration by three-dimensional computed tomography].

Routine chest radiographs of a 52-year-old woman displayed abnormal opacities in the right lower lung field. A computed tomographic (CT) scan of the chest disclosed irregular nodular opacities in the peripheral zone of the right S6. Reconstructed three-dimensional images obtained by helical CT displayed the lesions as agglutinated small nodules, with other small nodules near the bronchi appearing as "tree-in-bud" formations. Specimens obtained by transbronchial lung biopsy of the right B6b revealed atypical glandular structures, thus leading to suspected adenocarcinoma of primary lung cancer. A right lower lobectomy was performed; cut-surface specimens of the resected tissues showed multiple lobulate, milky-white nodules near the bronchi. Histopathologic examination found no malignant cells. PAS staining revealed numerous cryptococcal organisms, thus yielding the final diagnosis of primary pulmonary cryptococcosis.