Supplementary Material for: Unusual metastatic lymph node to retro-scapular area in occult breast cancer, a case report

Introduction: Breast cancer typically metastases to axillary, internal mammary and supraclavicular lymph node chains. In contrast, occult breast cancer (OBC), a rare form of breast cancer, usually presents as axillary lymphadenopathy, and rarely metastasize regionally or distally. Case presentation: In this case report, we present a 45-year-old female patient with unusual presentation of breast cancer initially as axillary lymphadenopathy without breast mass. She was diagnosed by magnetic resonance imaging (MRI) as OBC, and later presented with a rare pathological spread to the ipsilateral subscapular region. The retro-scapular nodal disease was first detected via follow up computed tomography (CT) scan and confirmed by positron emission tomography (PET) after 18 months of her initial diagnoses. This occurred following completion of OBC management, which included neoadjuvant chemotherapy, axillary lymph node dissection, without mastectomy, followed by adjuvant radiation treatment to regional lymph nodes and ipsilateral whole breast. Her recurrent nodal disease was subsequently managed by surgical resection followed by radiation therapy to surgical bed. This case report emphasizes the diverse locations where metastatic breast cancer can manifest and underscores the advancements in diagnostic tools that have enhanced the detection of these metastatic sites.