Extravascular migratory metastasis in gynaecological carcinosarcoma

Area of Science:

• Oncology
• Pathology
• Gynaecology

Background:

• Extravascular migratory metastasis (EVMM) is a known tumor spread mechanism, primarily documented in cutaneous melanoma.
• EVMM has not been previously described in gynecological malignancies.

Purpose of the Study:

• To describe the occurrence of EVMM in gynecological carcinosarcomas.
• To investigate the characteristics of EVMM in these tumors.

Main Methods:

• Retrospective examination of 24 gynecological carcinosarcomas (11 tubo-ovarian, 12 endometrial).
• Identification and characterization of EVMM using routine diagnostics and immunohistochemistry (SMA, CD31, CD34, D2-40, laminin, type IV collagen).

Main Results:

• EVMM was identified in four gynecological carcinosarcomas.
• Malignant cells in EVMM exhibited a sarcomatoid appearance, located abluminally around vessels, with some showing mural fibrin deposition.
• Perivascular tumor cells demonstrated stronger SMA and laminin immunoreactivity compared to non-vascular tumor elements.

Conclusions:

• EVMM is a newly recognized mechanism of tumor spread in gynecological carcinosarcomas.
• The perivascular tumor cells may adopt a pericytic phenotype, indicative of a specific epithelial-mesenchymal transition pattern.
• Further research using pericyte-specific markers is warranted to explore the prognostic significance of EVMM in gynecological tumors.