Pathology of cerebral embolization caused by nonthrombotic agents

Neurological complications of systemic cancer

Neurological complications of systemic cancer-those arising outside the nervous system-can be distressing, disabling, and sometimes fatal. Diagnosis is often difficult because different neurological disorders may present with similar signs and symptoms. Furthermore, comorbid neurological illnesses, common in elderly patients with cancer, can complicate diagnosis. Early diagnosis and aggressive treatment can improve neurological symptoms and can substantially enhance a patient's quality of life. We approach the problem of neurological complications of systemic cancer as would a neurologist: first by identifying the anatomical area or areas that are affected (ie, brain, spinal cord, peripheral nerve), then by evaluating the diagnostic approach, considering the symptoms and signs and including appropriate laboratory tests, and finally, by recommending treatment. We focus on disorders that are difficult to diagnose, need neurological consultation, and for which effective treatments exist.

Brain embolic phenomena associated with cardiopulmonary bypass

Various biologic and non-biologic materials may be embolized to the brain after the use of cardiopulmonary bypass (CPB) pumps during open heart surgery but their relative frequency and importance are uncertain. Among the nonbiologic materials, Antifoam A, which contains organosilicates and silicon, continues to be employed as an additive to prevent frothing. Recent improvements in filtration and oxygenation techniques have clearly reduced the incidence of large emboli and complications like stroke but other neurologic sequelae following open heart surgery are common and in many cases poorly explained. A recently developed histochemical technique for the demonstration of the endothelial alkaline phosphatase (AP) was employed in a post-mortem study of brains from 8 patients and 6 dogs dying within a few days after open heart surgery employing cardiopulmonary bypass perfusion. Brains from 38 patients and 6 dogs who were not subjected to heart surgery were studied as controls with the same technique. The AP-stained slides are suitable for both light microscopic examination of the thick celloidin sections as well as a subsequent processing for high-resolution microradiography. Small capillary and arteriolar dilatations (SCADs) were seen in the test subjects/animals but not controls. SCADs were seen in all parts of the brain. Approximately 50% of the SCADs showed birefringence when examined with polarized light. SCADs are putative embolic phenomena and the exact nature and source of the embolic material is under investigation. A glycolipid component is indicated by preliminary studies. SCADs are difficult to find in routine paraffin sections and most if not all of the offending material seems to be dissolved during processing.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain microemboli during cardiac surgery or aortography

We have observed many focal dilatations or very small aneurysms in terminal arterioles and capillaries of 4 of 5 patients and 6 dogs who had recently undergone cardiopulmonary bypass. A smaller number of sausagelike dilatations distended medium-sized arterioles. Two other patients had a small number of the same microvascular changes following proximal aortography. Thirty-four patients and 6 dogs not undergoing cardiopulmonary bypass had none. (A 35th patient who had not undergone cardiopulmonary bypass or aortography showed a small number of dilatations; mediastinal air was a suggested source.) Some of the dilatations exhibited various forms of birefringence. Because most of the dilatations appear empty, we speculate that they are the sites of gas bubbles or fat emboli that have been removed by the solvents used in processing. These microvascular events, occurring only in conjunction with major arterial interventions, may be the anatomical correlate of the neurological deficits or moderate to severe intellectual dysfunction seen in at least 24% of patients after cardiac surgical procedures assisted by cardiopulmonary bypass.

Neoplastic cerebral aneurysm from lung cancer. Case report

A 56-year-old man with lung cancer developed a massive intracerebral hematoma resulting from rupture of a small neoplastic aneurysm in a cortical branch of the left posterior temporal artery. Histologically, undifferentiated squamous cells formed an embolus in the aneurysm and destroyed the aneurysm wall. No tumor mass was evident around the aneurysm.

Cerebral fat embolism following cardiac surgery

We describe 3 cases of cerebral fat embolism associated with cardiac surgery. The autopsy findings suggested that in 2 cases, the embolic fat globules entered the systemic circulation directly as a result of protrusion of epicardial fat into the left atrial chamber along the suture line in one case, and through an atrial septal defect in the other. The characteristic latent interval between surgical trauma and onset of neurologic manifestations was lacking in both cases. The evolution of neurologic manifestations and the pathologic findings in the third case were similar to those usually seen in posttraumatic fat embolism. This study suggests that the pathogenetic mechanisms of cerebral fat embolism following cardiac surgery may vary in different cases. Also, it emphasizes the importance of autopsy in the investigation of this serious but preventable complication.

Neoplastic aneurysm and intracranial hemorrhage

A case of fatal intracerebral hemorrhage due to rupture of a neoplastic aneurysm in a 68-year-old man with a history of bronchogenic carcinoma is reported. Intracranial neoplastic aneurysms resulting from metastatic tumor embolization of the cerebral vessels are more often associated with cardiac myxoma and choriocarcinoma. Of the 23 reported cases, eight ruptured and caused intracerebral or subarachnoid hemorrhage. Like mycotic aneurysm, they are small and located in the peripheral branches of cerebral artery, and may easily be obscured by hemorrhage when ruptured.

Cerebral fat embolism: a neuropathological study of a microembolic state

Multiple cerebral petechiae associated with intravascular globules of neutral fat and localized primarily within the white matter are distinctive lesions which secure the pathologic diagnosis of cerebral fat embolism. The abundance of these lesions in an unknown, but presumably small, percentage of cases of fat embolism, along with the even more widespread distribution of embolic fat droplets throughout both white and gray matter, suggest that these lesions and emboli must have a profound effect on neurologic function. Nevertheless, respiratory insufficiency is by far a more common clinical manifestation of the fat embolism syndrome and the neurologic involvement of such patients is often attributed to the secondary effects of generalized hypoxia. The following patient with overt respiratory and neurologic symptoms re-emphasizes the direct primary effect of fat emboli within the central nervous system as a cause of white matter hemorrhages and neurologic deterioration. Explantations for the selectivity of the lesions for the cerebral white matter are explored.

Internal carotid artery embolism by shotgun pellet

Various examples of foreign body embolization of cerebral arteries, usually followed by serious consequences, have been reported (Lindberg et al., 1961; Chason et al., 1963; Steele et al., 1972; Wetli et al., 1972). However, a shotgun pellet entering the left atrium of the heart through a gunshot wound of the chest with subsequent embolic occlusion of one of the carotid arteries appears to be unique. It is the subject of this short communication.