Clinical and radiologic findings in a 73-year-old man who developed a
systemic illness while receiving intravesical bacillus Calmette-Guerin
(BCG) immunotherapy for bladder cancer are presented. Thin-section ch
est computed tomographic findings included a diffuse pattern of small
nodules consistent with miliary disease. Potential mechanisms explaini
ng the pulmonary disease resulting from intravesical BCG treatment inc
lude a hypersensitivity reaction or actual BCG infection of the lungs.