A 75-year-old man is brought to the emergency department due to 2 hours of left-sided chest pain and dyspnea. The patient has lived in a skilled nursing facility since developing right-sided hemiplegia, hemi-sensory loss, and aphasia 4 months ago. He has a history of diabetes mellitus, hypertension, and hypercholesterolemia. As an ECG is being obtained, the patient develops ventricular fibrillation and dies despite resuscitative efforts. An autopsy is performed; a coronal section of the brain is shown in the image below. The walls of the brain lesion are most likely composed of which of the following?

Question

A 75-year-old man is brought to the emergency department due to 2 hours of left-sided chest pain and dyspnea.  The patient has lived in a skilled nursing facility since developing right-sided hemiplegia, hemi-sensory loss, and aphasia 4 months ago.  He has a history of diabetes mellitus, hypertension, and hypercholesterolemia.  As an ECG is being obtained, the patient develops ventricular fibrillation and dies despite resuscitative efforts.  An autopsy is performed; a coronal section of the brain is shown in the image below.  The walls of the brain lesion are most likely composed of which of the following?

Quizplus · Accepted Answer

11ec160b_39cc_3c9c_9249_73420936c342_MD0001_00 The coronal section of this patient's brain shows a cystic lesion caused by ischemic stroke involving the left cerebral hemisphere (eg, cortex, subcortical white matter, putamen). Neuropathology coronal sections are oriented with the right side of the brain on the examiner's right side. Thrombosis of atherosclerotic plaques involving the cerebral arteries can result in vessel occlusion with tissue hypoxia and subsequent necrosis. Ischemic neuronal injury initially causes intense cytoplasmic eosinophilia ("red neurons") followed by neutrophil infiltration a day later. After several days, macrophages/microglia are recruited to phagocytize the necrotic debris and predominate in the ensuing 2-3 weeks. Around this time, the periphery of the necrotic area becomes populated with new blood vessels and proliferating astrocytes that form a network of cytoplasmic extensions (reactive gliosis). Several months to years after brain infarction, the necrotic area appears as a cystic cavity surrounded by a wall composed of dense fibers formed by astrocytic processes (glial scar). (Choice B) Ependymal cells are ciliated glial cells that line the ventricles and central canal of the central nervous system and make up the choroid plexus. These cells produce cerebrospinal fluid but do not directly participate in glial scar formation around old infarcts. (Choice C) Large ischemic strokes may result in perivascular fibroblast infiltration with fibrotic scar formation within the core of the lesion. However, this region remains separated from normal brain parenchyma by a wall of reactive gliosis, which protects viable neuronal tissue from being damaged by the fibrotic inflammatory response. (Choice D) Oligodendrocytes are the myelin-producing cells of the central nervous system and do not directly participate in glial scar formation around old infarcts. (Choice E) The meninges (eg, pia mater) are separated from the cystic cavity created after ischemic stroke by a gliotic tissue layer (derived from the cortex) and do not participate in glial scar formation. (Choice F) Schwann cells are myelin-producing cells that help guide axonal repair and regeneration in the peripheral nervous system. Educational objective: Several months to years after ischemic brain infarction, the necrotic area appears as a cystic cavity surrounded by a wall composed of dense fibers formed by astrocytic processes (glial scar). __________ References: Glial scar formation occurs in the human brain after ischemic stroke. (http://www.ncbi.nlm.nih.gov/pubmed/24578611) Role of the lesion scar in the response to damage and repair of the central nervous system. (http://www.ncbi.nlm.nih.gov/pubmed/22362507)

A 75-Year-Old Man Is Brought to the Emergency Department Due