Supplemental Table 2. Detailed Patient Information.
| Age/Sex | Primary Location | Signs & Symptoms | Metastasis Locations | First Identifying Imaging | Primary Treatment | Metastasis Treatment | Outcomes |
| M 59 | Right tongue mass | Fever | LA & pericardium | CT & Echo | Partial glossectomy, right RND, CTX | Cardiac surgery | Death 3 weeks after surgery |
| F 45 | Tongue | Syncope & dyspnea | RV, LV, IVS | CTA & Echo | Partial right glossectomy, RND, RT. | RT (brain) | NR |
| F 36 | Tongue | Palpitations & SOB | LV | CT & Echo | CTX-RT, partial left glossectomy, and left neck LN dissection | RT | Death 2 months after |
| M 50 | Base of tongue | Odynophagia, otalgia, dysphonia, WL, tongue and neck pain | Apex of RV | PET-CT | 2 months radiation, total glossectomy & bilateral RND | None | NR |
| M 77 | NR | Recurrent syncope | RA & RV infiltration of myocardium | Echo | None | None | Death 28 days after diagnosis |
| M 54 | Tongue base | Dyspnea, LE edema, & hemoptysis | RV | CT & Echo | Glossectomy, left RND, cisplatin, 5-FU | None | Death |
| F 23 | Tongue | CP, Right arm paresthesias, cough, SOB | LV & RV infiltration of myocardium | Echo | Surgical resection with clear margins | None | NR |
| M 28 | Tongue | Recurrent syncope | RA, LV, IVS | Echo | Hemimandibulectomy & post-operative RT | Pacemaker implantation | Death 5 days after pacemaker placement |
| M 47 | Tongue | Dizziness, SOB, chest tightness, night sweats | RA, RV, pulmonary artery | CT chest | Surgical excision with CTX-RT | None | Patient lost to follow-up |
| F 61 | Base of tongue | CP, palpitations | RA & pericardium | Echo | Hemiglossectomy with excisional biopsy of digastric LN. Neck RT | None | Death 7 weeks after cardiac diagnosis |
| F 32 | Right. lateral tongue | Nasal swelling | LV & IVS | PET-CT scan | Wide excision & right lateral neck dissection | CTX | Follow-up CT stable |
| M 46 | Right vallecula | N/A (Follow-up) | RV | Endoscopy | CTX-RT | CTX | Patient lost to follow-up |
| F 66 | Tongue | Anginal symptoms | RV | Coronary angiogram | Radical resection | None | NR |
| M 57 | Anterior tongue | Fever, dyspnea | Epicardium, myocardium, endocardium | Echo | Partial glossectomy | CTX | Death 14 days after admission from sepsis |
| M 43 | Tongue | N/A (Follow-up) | Apex of LV & RV | CT & Echo | CTX-RT | CTX | Death due to cardiac metastasis |
| M 61 | Left tongue base | Cerebral infarction symptoms | LAA and pulmonary vein | CT & Echo | CTX-RT | None | NR |
| M 76 | Tongue | Pneumonia | RV, LV | CT chest | Partial glossectomy, multiple neck dissection, CTX | Palliative care | Died in one month |
| M 61 | Tongue | CP, dyspnea | IVS and pericardium | 99mTC scan | RAD | None | Death |
| M 62 | Tongue | Malaise | Diffuse myocardium | 99mTC scan | NS | None | Death |
| M 43 | Right tongue | N/A (Follow-up) | RV, LV | CT chest | Right neck dissection & tongue resection, free flap reconstruction, CTX-RT | CTX-RT | Death |
| F 46 | Left lateral tongue | Left arm, ear, and throat pain | LV, pericardium | CT | Hemiglossectomy, bilateral neck dissection, CTX-RT | CTX-RT | NR |
| M 59 | Tongue | Chest discomfort | RV | Echo | Resection, RT | None | Death |
| M 63 | Tongue | Dyspnea | RV | Echo | Resection and reconstruction | None | NR |
| F 57 | Tongue | Death | RA, AV sulcus | Autopsy | Hemiglossectomy, bilateral cervical lymphadenectomy, CTX-RT | None | Death |
| M 66 | Right tongue into oropharynx | Death | LV, IVS | Autopsy | Total glossolaryngectomy and dissection LN bilaterally | None | Death |
| M 57 | Right tongue base | Lower extremity edema | RV | Echo, ECG, CMRI, CT | Local excision with post-operative RT to lesion and neck | CTX | Death |
| F 48 | Anterior tongue | CP, dyspnea, hemoptysis, anorexia. | Diffuse myocardium, RA, LV, aortic valve | NR | Anterior tongue glossectomy, excision of submandibular LN | None | Death |
| F 58 | Tongue | CP | NR | CT | Hemiglossectomy and RT | Palliative CTX and immunotherapy | Death |
| F 70 | Tongue | Fever & chills | Diffuse pericardium | CT | Left hemiglossectomy, RND | Thoracotomy | Death |
| F 52 | Tongue | Dull CP | RV, LV, IVS | PET | Hemiglossectomy and RND | Pericardial window and palliative care | Life expectancy < 3 months |
| M 60 | Base of tongue | Malnutrition, pneumonia | Anterior wall of RV & pulmonic valve | Echo | RT and a composite tongue-jaw-neck resection | Palliative care | Death |
Abbreviations: 5-FU = 5-fluorouracil; 99mTC = Technetium 99; CMRI = cardiac magnetic resonance imaging; CP = chest pain; CT = computed tomography; CTA = computed tomography angiography; CTX = chemotherapy; CTX-RT = chemotherapy/radiation; Echo = echocardiogram; IVS = interventricular septum; LA = left atrium; LAA = left atrial appendage; LE = lower extremity; LN = lymph node; LV = left ventricle; MRI = magnetic resonance imaging; NR = not recorded; NS = non-surgical; PET = positron emission tomography; PET-CT = positron emission tomography-computed tomography; RA = right atrium; RND = radical neck dissection; RT = radiation therapy; RV = right ventricle; SOB = shortness of breath; WL = weight loss.