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