Mesenchymal hamartoma of the chest wall.

Mesenchymal hamartoma of the chest wall is an unusual lesion remarkable for its occurrence in early infancy and alarming clinical presentation, which often suggests malignancy. Despite its aggressive appearance and propensity to attain massive size, the lesion behaves biologically in a benign fashion, and may be treated conservatively, provided that there is no respiratory compromise secondary to mass effect. The case of an incompletely resected mesenchymal hamartoma that has behaved in a benign fashion after more than 4 years of follow-up is discussed here. We present this case to provide insight and raise clinicians' awareness of the behavior of an extremely rare tumor.