Two cases of mesenchymal hamartoma of chest wall in infancy are reported. These distinctive and rare lesions arise in the antenatal period, present at birth or in early life as chest wall masses with marked rib deformation, and may produce respiratory compromise through encroachment on the chest cavities. Histologically composed of chondroid and primitive mesenchymal elements with giant-cell formation, endochondral ossification, and maturation to trabecular bone, they exhibit some features of aneurysmal bone cyst. Because of their cellularity and proliferative appearance, they are often misinterpreted as sarcomas; however, they pursue a benign course and can be well managed surgically. Our cases possessed multiple chest wall masses that were clinically apparent at birth and sequentially resected over a period of several months, creating an opportunity to document their hitherto unreported histologic evolution. Their pattern of maturation is in keeping with a hamartomous malformation.

Gorham's disease, also called massive osteolysis or vanishing bone disease, is an enigmatic condition caused by endothelial proliferation occurring in bone and soft tissue. Death is frequent when there is spinal or visceral involvement. We present a case of spinal and skull base Gorham's disease that was reversed by radiation therapy administered while the spine was supported by a halo vest. The literature is reviewed.

We report a female infant who presented at birth with an unusual syndrome of disseminated cutaneous and gastrointestinal vascular malformations associated with severe thrombocytopenia and chronic gastrointestinal hemorrhage. The infant required extensive blood-product support and expired at 7 months of age. Postmortem examination confirmed the presence of numerous flat vascular lesions, descriptively classified as angiodysplastic, and composed of congeries of dilated capillaries, arterioles, and postcapillary venules. No visceral space-occupying hemangiomas were found. The case is discussed in relation to a spectrum of congenital vascular malformation syndromes including disseminated neonatal hemangiomatosis and hereditary hemorrhagic telangiectasia (HHT). Some pathologic characteristics appear to link it to the latter entity. However, other clinical and pathologic features distinguish it from the reported spectrum of congenital HHT, prompting its essentially descriptive designation.