A 56-year-old man dies in the hospital due to aspiration-related complications. The patient was admitted 5 days ago with right-sided weakness, sensory loss, and difficulty with speech and swallowing. CT scan revealed an area of hypodensity in the left frontoparietal region. Autopsy examination is performed, and a section of loose, spongy tissue from the abnormal brain area is obtained. Histologic findings after staining for lipids are shown below. The cells most intensely stained in this patient's brain specimen represent which of the following cell types?

Question

A 56-year-old man dies in the hospital due to aspiration-related complications.  The patient was admitted 5 days ago with right-sided weakness, sensory loss, and difficulty with speech and swallowing.  CT scan revealed an area of hypodensity in the left frontoparietal region.  Autopsy examination is performed, and a section of loose, spongy tissue from the abnormal brain area is obtained.  Histologic findings after staining for lipids are shown below.  The cells most intensely stained in this patient's brain specimen represent which of the following cell types?

Quizplus · Accepted Answer

11ec160b_39c9_a487_9249_255f199bde91_MD0001_00 This patient developed acute-onset neurologic defects (eg, hemiparesis, dysphagia, dysarthria) secondary to an ischemic stroke, which was confirmed by CT scan and autopsy findings. An ischemic infarct results from regional hypoperfusion (eg, thrombosis, embolism) or a global decline in cerebral blood flow. Characteristic CT findings are evident 6-12 hours after the onset of ischemic injury and include hypoattenuation of the tissue and loss of grey-white matter differentiation within the affected region. Microscopically, neurons in the necrotic area display signs of irreversible damage during the first 24 hours after injury (red neurons). Neutrophils initially move into the area in the first 1-2 days, followed by microglia (derived from yolk-sac monocytes) 3-7 days after the onset of ischemia. As the neurons disintegrate, their fragments are phagocytized by microglia, and myelin breakdown products accumulate in the cytoplasm of microglia as foamy lipids. Infiltration of the brain tissue by microglia (arrow) is seen on light microscopy in the photo and is consistent with the expected histology findings 5 days post-infarction. (Choices A and C) In peripheral tissues, fibroblasts migrate to the area of injury to participate in tissue repair. However, in the central nervous system, repair is instead performed by astrocytes that migrate to the area of necrosis within 2 weeks of injury to begin forming a glial scar. (Choices B and F) Although both ependymal cells and Schwann cells process lipids and would be prominent on lipid stain, neither type of cell participates in central nervous system repair after ischemic infarction. (Choice E) Neutrophils are the predominant type of inflammatory cell 1-2 days after cerebral infarction and release inflammatory mediators that contribute to the hydrolysis of cells in liquefactive necrosis. They would not be prominent on lipid stain. Educational objective: Microglia are the predominant cell in the necrotic area 3-7 days after the onset of ischemia and phagocytize the fragments of neurons, myelin, and necrotic debris.

A 56-Year-Old Man Dies in the Hospital Due to Aspiration-Related