Squamous cell carcinoma of unknown origin metastasising to the right atrium causing acute heart failure.

We describe a case of metastasis to the heart, which was initially suspected to be a myxoma, causing acute right heart failure. Emergency surgery was carried out by opening the right atrium and superior vena cava, and debulking the tumour in a piecemeal fashion, providing temporary relief of symptoms. The histology showed this to be metastatic squamous cell carcinoma possibly of head and neck origin. This is extremely rare, with few published cases. Full endoscopic and CT, including positron emission tomography CT, investigation of the head and neck was performed with no primary findings. Only two such cases of squamous cell carcinoma of unknown origin metastasising to the heart have been described, and, in both cases, the patients died within several weeks of diagnosis. This patient remains alive 2 months postoperatively and is receiving radiotherapy to the chest, but his prognosis remains poor.