IntroductionCardiac metastases are found in six to 20% of autopsies of patients with malignant neoplasm. The most common neoplasms that metastasize to the heart are malignant melanoma, lymphoma, and leukemia, but the relative numbers are greater with breast and lung cancers, reflecting the most common incidence of these cancers.Case presentationA 60-year-old Hispanic man presented to our hospital after being transferred from an outside hospital for workup and evaluation of an adrenal mass of the abdomen and pelvis, found on computed tomography. His chief complaint upon admission was altered mental status. Physical examination was unremarkable. He was alert and oriented and had a dry and non-erythematous oropharynx, and bilateral diffuse wheezing on lung examination. Computed tomography of the chest showed multiple hypodense lesions in the left ventricular myocardium, suggestive of metastases. There were also tiny sub-centimeter nodular densities in the right upper and lower lobes. Adrenal glands contained hypodense lesions, which showed characteristic adenocarcinomatous malignant cells.ConclusionCancers which have metastasized to the heart are found in six to 20% of patients with malignant neoplasms. The right side of the heart is more commonly involved in metastasis. This study is unusual in that a tumor of an unknown primary origin had metastasized to the left side of the heart.