Mesenchymal cystic hamartoma of the lung.

We report the case of an asymptomatic 51-year-old man, presenting with chest X-ray abnormalities consisting in multiple pulmonary nodules; the diagnosis of mesenchymal cystic hamartoma of the lung was made by an open lung biopsy, revealing both nodules of mesenchymal cells and cysts with a lining of normal or metaplastic epithelium. Clinical and pathological characteristics of this rare entity are reviewed.