Clinicopathologic features of collision tumor of breast myofibroblastic tumor with invasive breast cancer
HE Huizi
HOU Xiaoli
SHEN Nina
SHEN Liying
Abstract：Objective: To investigate the clinicopathological features of a collision tumor composed of myofibroblastoma of the breast combined with invasive breast carcinoma, and to enhance understanding of this disease. Methods: A retrospective analysis was conducted on the clinical manifestations, histopathological features, and immunophenotype of one case of breast collision tumor (myofibroblastoma combined with invasive breast carcinoma). Results: The patient was a 73-year-old female who had discovered a mass in the right breast for 2 years with ulceration. Breast MRI showed multiple irregular masses in the right breast. Microscopic examination revealed that the tumor consisted of two components: myofibroblastoma and invasive breast carcinoma, which were clearly demarcated and adjacent to each other. At the junction, invasive breast carcinoma was observed infiltrating into the myofibroblastoma. Immunophenotype: The myofibroblastoma component expressed CD34, Desmin, Vimentin, ER, PR, and showed loss of RB expression; the invasive breast carcinoma component expressed ER (80%++), PR (80%++), Ki-67 (40%+), and HER2 (2+). Conclusion: The collision tumor composed of myofibroblastoma of the breast combined with invasive breast carcinoma has not been reported in domestic or international literature so far. This disease is prone to misdiagnosis in pathological diagnosis, especially in core needle biopsy, and accurate diagnosis depends on histopathological examination after complete surgical removal of the lesion.
Keywords：MyofibroblastomaInvasive breast carcinomaCollision tumorPathological diagnosisSpindle cell tumor
Publication Date：2025-11-28
Online Publishing Date：2025-12-04(First online date of this platform, not the publication date of the document)
Pages：4( 1478-1481 )