Pectoralis muscle metastases from breast cancer in a young patient detected by automated breast ultrasound.

Metastases to the skeletal muscle from breast cancer represent an unusual and rare condition. We present the case of a 27-year-old female with left breast cancer (IDC NST G3) who underwent neoadjuvant chemotherapy followed by conservativesurgery (sectorectomy and lymphadenectomy) and radiation therapy. Two months after the end of radiotherapy she presented with a 2 mm skin lesion and she was referred for a screening ultrasound. The screening automated breast ultrasound (ABUS) revealed local recurrence and pectoralis metastases, lesions evaluated also by magnetic resonance imaging. The diagnosis was confirmed by the ultrasound-guided biopsy.