Mesenchymal hamartoma of the chest wall in an infant.

Mesenchymal hamartoma of the chest wall is a very rare, benign tumour with distinct clinical, radiological and histopathologic characteristics. The lesion develops during foetal life, and is present at or shortly after birth with an extrapleural mass arising from the rib cage with or without respiratory distress and marked rib deformity. Several imaging techniques have been used for diagnosis, but a definitive diagnosis is established only by histopathological examination. Such lesions are composed of a varying admixture of hyaline cartilage that has features resembling growth plate cartilage, along with fascicles of spindle cells, woven bone and hemorrhagic cysts. Accurate diagnosis of mesenchymal hamartoma is important since many chest wall masses in children are malignant. We report a case of mesenchymal hamartoma of the left posterior chest wall surgically resected in an infant who was found to have a palpable mass at birth. Two years after surgery, the patient is alive and well, with no evidence of recurrence.