Bilateral chest wall mesenchymal hamartoma: Prenatal diagnosis and staged surgical resection

Mesenchymal hamartoma of the chest wall is a rare condition seen in infants. This case describes a prenatally diagnosed rapidly growing bilateral chest wall masses, suspected to be a mesenchymal hamartoma. Prenatal MRI performed at 33 weeks gestation showed large bilateral lesions with substantial mass effect in the form of pulmonary compression and displacement of the mediastinal structures necessitating delivery at our tertiary care facility at 35 weeks. At 48 hours post-birth, CTA revealed bilateral chest wall masses consistent with mesenchymal hamartoma and secondary aneurysmal bone cyst formation. The large left-sided lesion compressed the left lung and severely hindered pulmonary function, and the neonate required increasing respiratory support. The left-sided lesion was completely resected on day of life 15, and the neonate was extubated shortly after surgery. At the time of surgery the chest wall was reconstructed with alloderm, vicryl mesh and a latissimus dorsi advancement flap. A CTA at 3 months of age showed resection of the left-sided lesion with no evidence of recurrence, but significant growth in the unresected right hemithorax lesion. The right-sided lesion was resected uneventfully 8 months later. The prenatal and postnatal images showing the symptomatic lesion growth are discussed in this report.