An Immunohistochemical Anomaly: A Case Report and Systematic Review of Myofibroblastoma of the Breast

Myofibroblastoma (MFB) is a rare but benign mesenchymal tumor most commonly appearing within breast tissue. Most cases of MFB occur in postmenopausal women and are treated by surgical excision. The diagnosis of MFB is made through immunohistochemical (IHC) analysis, with the most common biomarkers being CD34+, desmin+, smooth muscle actin+, and vimentin+. In this article, we describe a case of an MFB in a premenopausal female with variance from classic IHC findings. We also performed a systemic review of the MFB of the breast. The systemic review compiles the most common IHC findings of MFB, patient demographics, treatment methods, lesion size, and the presence or absence of pain associated with the lesion. As MFB can share many features with other breast lesions, including potentially malignant ones, this article sought to underline the most common IHC findings and characteristics of MFB to aid in the proper diagnosis of MFB.