Cardiac metastasis in a patient with oral squamous cell carcinoma.

A 55-year-old man initially presented with an undifferentiated, HPV-p16-negative squamous cell carcinoma (SCC) in the left tonsillar region (cT4a N0 M0), which was treated with a combination of radiotherapy and chemotherapy. Several months later, the patient developed osteoradionecrosis on the left side of the mandible as well as a second primary lesion at the left base of the tongue. Surgical resection and mandibular reconstruction with a free vascularised fibula flap was performed. Regional clinical and radiologic follow-up showed no signs of tumour recurrence. However, routine positron emission tomography (PET)-CT showed a hypermetabolic mass intracardially. MRI confirmed the presence of a mass intramurally in the left ventricle, highly indicative of metastasis. Cardiac metastasis following oral cancer is rare and usually asymptomatic. Therefore, it can be missed easily and is mostly described as a finding postmortem. Reporting these cases is important for contributing to the insight into the uncommon development of metastasis.