Clinical Report: Two Cases of Breast Secretory Carcinoma with ETV6-NTRK3 Fusion

Background

Secretory carcinoma of the breast is a rare malignancy, comprising less than 0.15% of all breast carcinomas. It is characterized by specific morphological features and a frequent triple-negative immunophenotype.

Data Highlights

Key Findings

• Both cases exhibited characteristic morphology of SCB, including microcystic and solid growth patterns.
• Immunohistochemistry revealed a triple-negative phenotype with diffuse S-100 and CK5/6 positivity.
• ETV6-NTRK3 fusion was confirmed by FISH in both tumors.
• Case 1 had no nodal metastasis, while Case 2 had sentinel lymph node metastasis.
• Both patients received adjuvant chemotherapy and radiation therapy.
• No locoregional recurrence or distant metastasis was observed during follow-up.

Clinical Implications

The integration of morphology, immunohistochemistry, and molecular testing is crucial for the accurate diagnosis of SCB.

Conclusion

These cases highlight the diagnostic challenges of SCB.

Related Resources & Content

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