Cytokeratin AE1/AE3 immunolabeling in epithelioid hemangiosarcoma

Area of Science:

• Veterinary Pathology
• Oncology
• Immunohistochemistry

Background:

• Epithelioid hemangiosarcoma (EH) is a rare vascular tumor affecting multiple species, including dogs.
• EH exhibits epithelioid cell morphology, mimicking epithelial neoplasms.
• Cytokeratin AE1/AE3 (CK AE1/AE3) expression in human EH poses diagnostic challenges, potentially confusing it with carcinomas.

Purpose of the Study:

• To evaluate CK AE1/AE3 immunolabeling in canine epithelioid hemangiosarcoma.
• To compare canine EH CK AE1/AE3 expression patterns with those reported in human cases.
• To determine the utility of CD31 and CK AE1/AE3 immunohistochemistry in diagnosing canine EH.

Main Methods:

• Retrospective analysis of 30 canine EH cases from five veterinary institutions.
• Immunohistochemistry performed for CD31 and CK AE1/AE3.
• Assessment of CK AE1/AE3 cytoplasmic and membranous immunolabeling patterns.

Main Results:

• CK AE1/AE3 immunolabeling was observed in 43% (13/30) of canine EH cases.
• Cytoplasmic CK AE1/AE3 labeling varied from 5% to 100% of neoplastic cells.
• All tumors showed consistent membranous CD31 immunolabeling, confirming vascular origin.

Conclusions:

• Canine EH exhibits similar CK AE1/AE3 immunolabeling patterns to human EH, presenting a comparable diagnostic challenge.
• CD31 is a reliable marker for identifying vascular tumors like EH in dogs.
• Vascular markers such as CD31 should be included in the diagnostic workup for suspected EH, especially in small biopsies.