Rare case of squamous cell carcinoma of buccal mucosa metastasizing to interventricular septum in a young adult detected by 18F-FDG PET-CT

Metastatic tumors to the heart unlike primary cardiac tumors are not rare. Despite its frequency, cardiac metastasis is commonly detected only during autopsy as the symptoms of disseminated metastasis prevail over symptoms caused by cardiac metastasis and hence is overlooked most of the time. Tumors more commonly found metastasizing to the heart are malignancies of lung, breast, esophagus, lymphoma, leukemia, and malignant melanoma. Head and neck malignancies have a lower incidence of distant metastasis when compared to other malignancies and it rarely causes cardiac metastasis. Here we report the case of a 32 year old Indian male with squamous cell carcinoma of buccal mucosa who underwent surgery followed by chemoradiation. Follow up, FDG PET-CT showed extensive lymphnodal, pulmonary & skeletal metastasis apart from local recurrence in the tongue and floor of mouth. Another discrete foci of increased FDG uptake was noted in the region of heart which corresponded to a hypodense foci in the interventricular septum in contrast enhanced CT raising the possibility of cardiac metastasis. Subsequently, 2D echocardiogram with parasternal long axis view showed hyperdense anterior septum with speckled appearance with a hyperechoic structure attached to the septum towards the right ventricular side confirming metastatic deposit to the heart.