Abstract

Myofibroblastoma (MFB) is a rare stromal benign tumor that arises from the breast tissue, composed by fibroblasts, myofibroblasts and adipocytes. MFB typically presents as a solitary, painless mass in the breast,  predominates in 60-80 yearsold adult males and is rarer in postmenopausal women. It could be diagnosed by a combination of imaging and pathological tests, even if its imaging features are nonspecific, often leading to misdiagnosis. Biopsy is always needed for definitive diagnosis. Wide local excision, with no need of sentinel lymph node biopsy, is curative since local recurrence is extremely low and has been reported to be less than 1.5%. We report herein the case of MFB in a 61-year old male presenting with a nodule on the left breast and review the literature focusing on differential diagnosis.

Keywords: Myofibroblastoma; Breast cancer; Male breast;   usually diagnosed by a combination of imaging and pathological

MFB. tests, such as mammography, ultrasound, and biopsy, and diagnosis requires a correlation between clinical and instrumental findings.

Introduction

Case presentation

Breats MFB, or myogenic stromal (mesenchymal) tumor, of We report a case of a 61-year-old male, without family the breast is a rare benign tumor derived from mammary stromal history of breast cancer family history of breast cancer, presenting fibro-myofibroblasts, first described by Wargotz et al. in 1987 as with a palpable mass on the left breast, diagnosed and treated in a distinctive stromal tumor, nodular and well demarcated, formed the department of Propaedeutic surgery of the Aristotle University by uniform, slender, bipolar spindle cells [1]. It is composed of of Thessaloniki. Written informed consent was obtained from the a variety of cells including fibroblasts, myofibroblasts (spindlepatient for the publication of any potentially identifiable images shaped cells that play a role in the formation of connective tissue) or data included in this report. The patient was subjected to a CT and adipocytes. It is more common in male patients of older scan after noticing dizziness and fainting after starting a therapy age [2,3] and typically presents as a solitary, painless, movable, with alpha-blockers for prostatic hyperplasia. In CT scan was palpable  mass in the breast, usually not exceeding 3 cm of incidentally detected a dense, well-circumscribed, rounded mass, diameter, even if it is described from 2 mm to 18 cm [2,4,5]. It is without halo sign, in the left breast.

He presented with a nodule on the upper outer quadrant measuring 2 × 1,5 cm, well circumscribed, and freely movable. He had no skin or nipple retraction, and no palpable axillary lymph nodes.

Mammograhy (CC, MLO, Figure 1) showed a radiopaque, hyperdense mass in the upper-outer quadrant of the left breast, with a maximum diameter of 2,5 cm, without evidence of pathologic microcalcifications (BI-RADS 4c).

Figure 1: Mammography (CC, MLO) showinga radiopaque, hyperdense mass in the upper-outer quadrant of the left breast.

Ultrasound (US) revealed a hypoechoic mass with diameter of 2,2 x 1,53 cm, located at 2 o’clock position in the left breast, 2 cm far from the nipple, with unspecified boundaries and hypervascularized at color-doppler. No pathological findings were found in the right breast or in the axillary lymphnodes.

According to the US results a core biopsy was performed, and showed extensive occupation of small, ovoid, monomorphic neoplastic cells, without cellular or nuclear atypia and arranged individually or in small bundles, CD34+, ER+, demin+, with granular cytoplasmic staining in β-catenin, but negative in pancreatin and in STAT-6, compatible with MFB of the breast. 

Considering the radiological examination and the benign pathological findings a local excision was performed. The mass was well defined, demarcated and encapsuated, did not infiltrate the mammary gland, the skin or the pectoral muscle.

The histopathologic exam revealed macroscopically a 2,5 cm well-circumscribed, solid capsulated, pale white to grey round mass with nodulated surface (Figure 2).

Figure 2: Surgical specimen.

Microscopically, the mass consistsed on small, ovoid, monomorphic spindle cells arranged in haphazardly intersecting fascicles or clusters, thick hyalinized collagen bundles and low mitotic activity with a lack of cellular or nuclear atypia, myoepithelial component or necrosis, and arranged individually or in small bundles (Figure 3A, 3B).

Immunohistochemistry the lesion showed expression of CD34 (expressed on haematopoietic cells, or in mesenchymal stem cells), actin and desmin (patched). Estrogen, progesteron and androgen receptors were positive and pancreatin and STAT-6 were negative (Figure 3C and 3F).

After 12 months, the patient shows no signs of recurrence.