Enhanced magnetic resonance imaging features and management principles of low-grade myofibroblastic sarcoma of the breast: a case report.

Abstract

Background: Low-grade myofibroblastic sarcoma (LGMS) originating from breast is rare. Existing literature comprises clinical and pathological reports, with limited information on imaging characteristics. This study reports a case of LGMS of the breast and presents its imaging characteristics, with an emphasis on those observed using contrast-enhanced magnetic resonance imaging (MRI).

Case description: A 50-year-old patient presented with a left breast mass for 1 year. One year before the presentation, the patient had palpated a mass of approximately 1.5 cm in size in the upper part of the left breast without any obvious cause. The mass was perceived to be growing slowly. There was no relevant family history of breast conditions. Physical examination revealed a hard, ill-defined, irregularly shaped, non-tender mass of approximately 3.5 cm × 3 cm in size, with poor mobility and a close connection to the deep skin. The mammography showed a high-density mass without microcalcifications and boundary wrapping. Ultrasonography showed an oval, ill-defined hypoechoic mass. The combination of mammography and ultrasound examination results ruled out the possibility of ductal carcinoma and benign fibroepithelial tumor. On contrast-enhanced MRI, the mass exhibited heterogeneous enhancement, high signal intensity on T2-weighted imaging (T2WI), high signal intensity on diffusion-weighted imaging (DWI), and a type I time-intensity curve (TIC). A core needle biopsy (CNB) suggested a spindle cell tumor. To confirm the diagnosis, the patient underwent surgical excision, and postoperative pathology confirmed LGMS of the breast. The patient subsequently received adjuvant radiotherapy. Seven months postoperatively, bone scintigraphy suggested possible metastases.

Conclusions: LGMS of the breast exhibited a degree of malignancy on ultrasonography, mammography, and MRI, with the contrast-enhanced MRI showing a persistent enhancement pattern (type I TIC). A preoperative biopsy indicated a spindle cell tumor. Surgical excision remains the best diagnostic method. A thorough understanding of the imaging characteristics and biopsy results of this tumor type provides comprehensive information for formulating corresponding treatment plans.