Embolism of cerebral tissue to lungs: report of two cases and review of the literature.

Two patients with head injury and pulmonary emboli of brain tissue are described. Both patients developed persistent bleeding with elevations of prothrombin time, partial thromboplastin time, and decreased platelet counts. Postmortem examination identified multiple skull fractures, subdural and subarachnoid blood, cortical tears, and intraparenchymal hemorrhages. Lacerations of dural venous sinuses were documented in each case. Multiple pulmonary arteries contained plugs of cerebral tissue, including fragments of cerebral and cerebellar cortex, and white matter. The literature concerning brain tissue emboli is reviewed. In neonates, three patients who survived longer than 1 hour were found to have evidence of persistent hemorrhage. Among both children and adults, our two cases are the only ones reported with associated clotting abnormalities. Brain tissue embolism in neonates occurs after difficult vaginal deliveries, often in conjunction with the use of forceps. Tears of the tentorium cerebelli or falx cerebri have been documented at postmortem examination in the majority of these cases. By contrast, brain tissue embolism in children and adults occurs in association with severe closed or penetrating head injury. In several cases, as in the two reported here, postmortem examination has demonstrated a large cerebral venous defect as the probable site of entry of brain tissue into the systemic circulation.