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Analysis of Microglia and Monocyte-derived Macrophages from the Central Nervous System by Flow Cytometry
Published on: June 22, 2017
CD31 expression in intratumoral macrophages: a potential diagnostic pitfall
J K McKenney1, S W Weiss, A L Folpe
1Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
The American Journal of Surgical Pathology
|November 2, 2001
Summary
CD31 (platelet endothelial adhesion molecule) is commonly found in macrophages, not just endothelial cells. Misinterpreting CD31-positive macrophages can lead to incorrect vascular tumor diagnoses.
Area of Science:
- Immunohistochemistry
- Pathology
- Oncology
Background:
- CD31 (platelet endothelial adhesion molecule, PECAM-1) is a standard endothelial marker.
- Intratumoral CD31-positive macrophages have been mistaken for vascular sarcoma.
- Diagnostic confusion can arise from CD31 expression in non-endothelial cells.
Purpose of the Study:
- To determine the frequency of CD31 expression in macrophages in formalin-fixed, paraffin-embedded tissues.
- To assess how often CD31-positive macrophages cause diagnostic confusion, particularly regarding vascular tumors.
- To evaluate CD31 as a potential macrophage marker.
Main Methods:
- Reviewed 1950 consultation cases, focusing on 59 cases with CD31 immunostains.
- Analyzed CD31 expression in vascular and nonvascular tumors, correlating with morphology and other markers (CD34, CD68).
- Distinguished CD31-positive macrophages from endothelial cells and tumor cells.
Main Results:
- CD31-positive macrophages were identified in 81% of cases (48/59), including 87% of nonvascular tumors (34/39).
- Misinterpretation of CD31-positive macrophages led to erroneous vascular tumor diagnoses in 29% of relevant cases (4/14).
- CD31-positive macrophages were consistently CD34-negative and CD68-positive.
Conclusions:
- CD31 expression is frequent in macrophages, not exclusive to endothelial cells.
- Misidentification of CD31-positive macrophages can result in false diagnoses of primary vascular neoplasms.
- Recognizing the distinct staining pattern of CD31 in macrophages is crucial for accurate diagnosis; CD31 may serve as a macrophage marker.
