Differential diagnosis of primary mesenchymal neoplasms of the breast.

Objective: While the majority of breast neoplasms originate from epithelial cells, a rare part of them originate from mesenchymal breast tissue. This study aims to present the histomorphological and clinicoradiological features of our series of primary mesenchymal breast tumors and to discuss the features of these tumors in light of the literature.
Materials and Methods: Cases diagnosed as primary mesenchymal breast tumor in breast resection materials evaluated in our center between 2010 and 2023 were included.
Results: Of the 26 tumors included, 57.7% were diagnosed as benign and 42.3% as malignant mesenchymal tumor. Cases diagnosed as benign mesenchymal tumor were hemangioma, lipoma, extra-abdominal fibromatosis, leiomyoma, angiofibroma, lipomatosis, benign fibrous histiocytoma and granular cell tumor. Histopathological study results were compatible with angiosarcoma in 5 (45.4%), undifferentiated sarcoma in 3 (27.3%), myxofibrosarcoma in 2 (18.2%) cases and rhabdomyosarcoma in 1 (9.1%) case.
Conclusion: Primary breast sarcomas are rarely seen compared to benign mesenchymal tumors and constitute less than 0.1% of all malignant breast tumors. When histomorphological findings suggestive of a mesenchymal tumor are observed in breast specimens, sufficient sampling should be performed to exclude a possible phyllodes tumor, and clinicoradiological findings should be examined to exclude the possibility of a metastasis.
Competing Interests: Declarations. Conflict of interest: The authors declare that they do not have any conflicts of interest. Ethical approval: Ethical approval for this study was obtained from the Ethics Committee of Bursa Uludag University, Faculty of Medicine (Approval Number: 2023-11/4). Informed consent: Informed consent forms were not required from the patients in this retrospective study. Disclosure: There were no external sources of finding for the present study.
(© 2024. The Author(s), under exclusive licence to Federación de Sociedades Españolas de Oncología (FESEO).)