Epithelioid Myofibroblastoma of the Breast: A Report of Two Cases with Discussion of Diagnostic Pitfalls.

Mesenchymal lesions of the breast are uncommon lesions which present diagnostic dilemmas for even the most experienced pathologists. Here, we present two cases of the epithelioid-variant of myofibroblastoma which were misdiagnosed as malignant lesions. Careful integration of clinical presentation, imaging, and close examination of the gross, histologic, and immunohistochemical findings can assist in differentiating these challenging lesions and avoiding diagnostic pitfalls.