microglial nodule
Focal accumulation of activated microglia around sites of neuronal loss, indicating acute tissue injury or inflammation.
Full Definition
A microscopic aggregate of activated microglial cells that forms in response to acute neuronal injury, infection, or inflammatory processes in the central nervous system. These nodules represent sites where microglia have clustered to remove cellular debris through phagocytic activity, often surrounding dying neurons in a process called neuronophagia. Microglial nodules are particularly prominent in viral encephalitis, hypoxic-ischemic injury, and other acute pathological conditions that cause rapid neuronal death. The microglia within these nodules typically show enlarged cell bodies, shortened processes, and increased immunoreactivity for activation markers such as CD68 and Iba1. In chronic conditions, microglial nodules may persist as indicators of ongoing low-level tissue damage. Editorial attention should focus on distinguishing microglial nodules from other inflammatory infiltrates and providing appropriate context for their pathological significance.
Usage
Usage note: Specify underlying pathological context; quantify when describing distribution patterns.
In Context
- "Microglial nodules were distributed throughout the affected cortical regions in cases of viral encephalitis." — Autopsy findings
- "The formation of microglial nodules preceded significant neuronal loss in experimental ischemia models." — Research study