Abstract / Summary
Mucinous breast carcinoma (MBC) is an uncommon breast cancer subtype usually associated with favorable biology and infrequent nodal involvement, although giant heterogeneous tumors may create diagnostic and therapeutic challenges. We report a 63-year-old woman with a giant left-breast mucinous carcinoma and biopsy-proven axillary metastasis. Initial sampling was nondiagnostic, yielding only blood and fibrin. Contrast-enhanced MRI demonstrated extensive cystic-necrotic and hemorrhagic components with a discrete enhancing solid region, which was targeted during repeat ultrasound-guided core-needle biopsy and established the diagnosis. Neoadjuvant chemotherapy produced an initial partial response followed by limited further regression. Modified radical mastectomy with axillary dissection revealed substantial residual mucinous carcinoma with metastatic nodal involvement. At approximately 1 year after surgery, there was no imaging evidence of recurrence or distant metastasis. This case highlights the value of MRI-informed biopsy targeting and multimodality imaging for diagnosis and treatment-response assessment in giant heterogeneous MBC.