Brain Tissue Pulmonary Embolism Due to Severe Blunt Force Head Trauma in a Dog

A 9-week-old male puppy was submitted for necropsy examination after a reported history of developing acute melaena and vomiting blood before death. Grossly, the animal had multiple skull fractures, mostly affecting the occipital region and cranial floor, associated with extensive regions of subcutaneous, periosteal and subdural haemorrhages, as well as petechial haemorrhages within the right middle and caudal lung lobes. Histopathology of the brain revealed multifocal acute meningeal and parenchymal haemorrhage with laceration of the cerebellar folia. In the lung, multiple small- and medium-calibre branches of pulmonary arteries were occluded by aggregates of brain tissue, which exhibited weak immunoreactivity for glial fibrillary acidic protein and strong labelling for neuron specific enolase on immunohistochemistry. These findings were consistent with brain tissue pulmonary embolism, an infrequent phenomenon following severe head trauma. To the best of the authors' knowledge, this is the first reported case of canine brain tissue pulmonary embolism.