Myofibroblastoma of the Breast: Diagnostic Challenges of a Rare Benign Tumor

Abstract

Breast myofibroblastomas (MFBs) are rare benign tumors that have recently been recognized as a distinct entity. They are more common in men and often coexist with gynecomastia. Fine needle aspiration cytology or core biopsy should always be performed for triple assessment; however, due to the multiple variants of the tumor, final diagnosis can be safely accomplished only postoperatively with the aid of immunohistochemistry. The main histological characteristic that differentiates MFBs from the majority of malignant mesenchymal breast lesions is the presence of spindle cells in a collagenous background. Low mitotic activity and vimentin and CD34 positivity have been reported as well. Surgical excision retains a pivotal diagnostic and curative role. Local resection is sufficient, but mastectomy can also be advocated either in cases of male patients with coexisting gynecomastia or in females with large tumors. Into this retrospective survey, three cases of breast MFB were consecutively enrolled. Two patients were postmenopausal females and one was male. Relevant literature is briefly reviewed. Clinical features, histogenesis, morphological, and immunochemical findings are discussed, while the role of the current diagnostic and therapeutic management of this uncommon neoplasm is emphasized.

Keywords: Benign spindle stromal tumors; Breast lesions; Myofibroblastoma.

Fig. 1

U/S depiction of breast myofibroblastoma

Fig. 2

Histological section of the breast myofibroblastoma showing bundles of elongated cells with spindled nuclei (hematoxylin–eosin, ×100)

Fig. 3

Histological section of the breast myofibroblastoma showing extensive and intense cellular immunoreaction to vimentin (immunostain, ×100)

Fig. 4

Histological section of the breast myofibroblastoma showing positive cellular immunoreaction to desmin (immunostain, ×100)