Periductal stromal tumor of the breast; Can we expect the diagnosis? A case report and literature review

Introduction and importance

Periductal stromal tumors are rare breast neoplasms characterized by a unique combination of epithelial and mesenchymal tissue. Due to their infrequent occurrence, these tumors are often misdiagnosed as other breast lesions.

Case presentation

A 47-year-old female presented with a right breast swelling. She has a sister treated for breast cancer. Imaging revealed a central lesion of mixed density measuring 38 × 20 mm. The provisional diagnosis was a hamartoma BIRADS 3. The patient underwent wide local excision. Microscopic examination demonstrated biphasic fibroepithelial proliferation. The nodules comprised breast ducts lined by both epithelial and myoepithelial layers; some ducts were patent, while others were compressed into a slit-like configuration. However, the specimen lacked the leaf-like architecture. Immunohistochemical analysis revealed CD34 positivity in stromal cells, while Ki67 was positive in approximately 5 % of cells. The tumor cells were negative for Pan-CK and S-100. These findings led to the diagnosis of a right breast periductal stromal tumor.

Clinical discussion

The clinical presentation of PDST is often misleading. According to the recent pathological classification system, periductal stromal tumors are similar to phyllodes tumors but lack characteristic leaf-like structures. Immunohistochemical studies play a role in supporting the diagnosis. Complete surgical excision of the mass with negative margins is the standard of care.

Conclusion

Periductal stromal tumor is a rare breast neoplasm with potentially benign behavior. Complete excision is the standard management approach, which not only reveals the final diagnosis but may also help reduce the rates of local recurrence and malignant transformation.