Tenascin-C expression in Merkel cell carcinoma lymph node metastasis

Area of Science:

• Oncology
• Pathology
• Immunohistochemistry

Background:

• Tenenascin-C (Tn-C) expression correlates with invasion and metastasis in Merkel cell carcinoma (MCC).
• Cytokeratin-20 (CK-20) is a diagnostic marker for primary MCC.
• The role of Tn-C in MCC lymph node metastasis requires further clarification.

Purpose of the Study:

• To investigate and demonstrate the expression of tenascin-C (Tn-C) in Merkel cell carcinoma (MCC) lymph node metastases.
• To assess the utility of Tn-C as a marker for MCC metastasis in lymph nodes.
• To evaluate the expression patterns of Tn-C and CK-20 in metastatic MCC.

Main Methods:

• Immunohistochemical staining was performed on five metastatic lymph nodes.
• Monoclonal antibodies against Tn-C and CK-20 were utilized.
• Expression patterns were analyzed in relation to vascular structures, invasion borders, and fibrotic septae.

Main Results:

• All five metastatic lymph nodes showed positive expression of Tn-C.
• Tn-C expression was predominantly observed around vascular structures, invasion borders, and fibrotic septae.
• CK-20 expression varied, with one node strongly positive and others showing focal or negative patterns.
• Normal lymphoid tissue was negative for Tn-C, facilitating clear distinction from metastatic tissue.

Conclusions:

• Tenenascin-C (Tn-C) is a definitive marker for detecting Merkel cell carcinoma (MCC) metastasis in lymph nodes.
• Tn-C aids in distinguishing metastatic MCC from normal lymphoid tissue and demonstrating invasion.
• CK-20 expression in MCC metastases may be variable, unlike the consistent Tn-C expression.