Superior Vena Cava as Gateway to Heart: Metastatic Breast Carcinoma Causing Ball in a Loop Metastasis to Right Atrium

Breast carcinoma is the most common invasive cancer in women worldwide. It metastasizes commonly to bone, lungs, regional lymph nodes and brain. Cardiac metastasis of lung and breast cancers is a known but rare complication of advanced disease with tumour metastasising to pericardium via the locoregional lymphatic system. Here we present a case of 59-year-old female presenting with right upper limb oedema, facial puffiness and features of Superior Vena Cava (SVC) syndrome 15 years after mastectomy and adjuvant chemotherapy, radiotherapy for carcinoma of the right breast. Further evaluation revealed extensive thrombus invading the right internal jugular vein, subclavian vein, SVC with intraluminal extension into right atrium causing ball in a loop obstruction at tricuspid valve. Whole body Positron emission tomography scan confirmed the diagnosis of extensive metastatic disease and patient was managed on palliative therapy. Haematogenous spread and intraluminal growth of metastatic deposits from breast carcinoma 15 years ago is rare and clinical presentation as SVC obstruction has not been reported in our review of literature.