Placental transmogrification of the lung presenting as a small solitary nodule

Placental transmogrification of the lung is a rare cystic lesion of the lung, which has some histologic resembling to placental tissue. Placental transmogrification of the lung has been considered a variant of unilateral bullous emphysema, but in our case, the patient was a 47-year-old man who had no coexisting emphysema of the lung. Histologically our case showed an interstitial proliferation of clear cells with cystic change interpreted as secondary; we also agree with our colleagues that this proliferation may be the primary event pathogenetically. Surgical resection of this lesion seems to be curative.