Mesenchymal cystic hamartoma presenting with pneumothorax: case report and review of the literature.

Mesenchymal cystic hamartoma (MCH) of the lung is a rare disease, with an indolent course in the majority of cases. It can be single or multifocal and it is composed of primitive mesenchymal cells admixed with cystic spaces. Only few cases have been reported in the literature, with variable clinical presentation. We describe the case of a huge MCH, presenting with spontaneous pneumothorax in a 65-year-old man. Further, we provide a brief overview of the literature and discuss the differential diagnosis with other entities, and the possible diagnostic pitfalls.