[A case of alveolar microlithiasis which developed spontaneous pneumothorax due to progression of emphysematous bullae during 34 years after established diagnosis].

The patient was a 46-year-old man who was taxi driver. He had received therapy for miliary tuberculosis from nine years old, and the diagnosis of alveolar microlithiasis was made by open lung biopsy at twelve years of age in 1956. At that time, there were no emphysematous bullae, and slight alveolar wall thickening was observed histopathologically. After a 34 year interval, he developed spontaneous pneumothorax with sudden dyspnea. Multiple emphysematous bullae were found at thoracoscopy performed to treat the pneumothorax. Arterial blood gas analysis after resolution of the pneumothorax showed hypoxia with a PO2 of 65.4 torr, and lung function tests revealed restrictive disorder. Thus, in this patient, emphysematous bullae progressed resulting in a pneumothorax, and lung fibrosis also developed 34 years after the diagnosis of alveolar microlithiasis. Alveolar microlithiasis is occasionally misdiagnosed as miliary tuberculosis. The authors stress that the chest roentgenographic finding of ari-bronchogram demonstrating intra-alveolar foci is an important sign in the differential diagnosis.