Myofibroblastoma of the Breast

Abstract

This study aimed presenting a case of a 64-year-old woman with a rare diagnosis of myofibroblastoma (MFB). MFB is one of the rare, benign, spindle-like stromal tumors arising from the connective tissue of the breast. MFBs are often confused with fibroadenomas and hamartomas because of their benign characteristic appearance on breast imaging and are diagnosed after excisional biopsies. Their differential diagnosis with malignant neoplasia of the breast is important because of their wide morphological spectrum. Our case also demonstrated a breast mass with benign imaging characteristics and a needle core biopsy revealing a benign, spindle-like stromal tumor. The pathological examination performed after the excision of the lump demonstrated a collagenous-/ fibrous-type MFB. This case report emphasizes the rare but important place of MFB variants of the breast in the differential diagnosis of breast mass.

A case report and literature review: post-traumatic mammary myofibroblastoma

“…Microscopically, MFB can be classified into 5 subtypes: classical, collagenase, cellular, epithelioid, and infiltrative. 8 The majority of MFB are immunoreactive for CD34, desmin, smooth muscle actin, and vimentin. On the other hand they are usually negative for cytokeratin and S-100 protein.…”

A case report of a mammary myofibroblastoma in a male and literature review of radiologic and pathologic features of breast myofibroblastoma

“…In the macroscopic view, the cut of a myofibroblastoma shows a well demarcated pink or tan round mass . In histopathology, myofibroblastoma is presented as some bipolar spindle‐shaped cells showing variable myogenic and fibroblastic differentiation in short intersecting fascicles interrupted by keloidal like eosinophilic collagen bands . In immunohistochemistry, myofibroblastoma stains positively for Vimentin, Desmin, and CD34.…”

“…Myofibroblastoma can show different variants using histological patterns. Variants identified included classic, cellular, collagenous/fibrous, lipomatous, infiltrative, myxoid, epithelioid, and decidua‐like variants . Epithelioid type and cellular type of myofibroblastoma can mimic the histologic features of invasive lobular carcinoma and metaplastic breast carcinoma, respectively.…”

“…25 In histopathology, myofibroblastoma is presented as some bipolar spindle-shaped cells showing variable myogenic and fibroblastic differentiation in short intersecting fascicles interrupted by keloidal like eosinophilic collagen bands. 25,26 In immunohistochemistry, myofibroblastoma stains positively for Vimentin, Desmin, and CD34. Positively stained with estrogen, progesterone, androgen receptors, SMA, S100, bcl-2 and negatively for CD31, and cytokeratin are detected in some types of myofibroblastoma.…”

“…Variants identified included classic, cellular, collagenous/fibrous, lipomatous, infiltrative, myxoid, epithelioid, and decidua-like variants. 26 Epithelioid type and cellular type of myofibroblastoma can mimic the histologic features of invasive lobular carcinoma and metaplastic breast carcinoma, respectively. The negative staining for cytokeratin can help in differentiating these tumors 27,28 The long term prognosis is good for myofibroblastoma, and excisional biopsy is usually sufficient for the treatment of myofibroblastoma.…”