Spontaneous regression of large-cell carcinoma of the lung--a rare observation in clinical practice.

Spontaneous regression of non-small-cell lung carcinoma is extremely rare and there are few documented cases. We report a 59-year-old man with a right upper lobe tumour which showed progressive regression while hilar adenopathy appeared 2 months after the initial tumour detection. At operation, only scar tissue was found in the lung but a hilar lymph node contained large-cell undifferentiated carcinoma. This report indicates that a decrease in size of a pulmonary mass does not exclude the diagnosis of carcinoma and that metastatic disease can occur even if the primary tumour regresses.