however , cardiac metastasis is diagnosed in less than 1% of patients with malignant melanoma because less than 10% of these patients present with cardiac symptoms.1 - 3 ) identification of cardiac metastasis from melanoma usually means that the patient is suffering systemic metastasis . unlike typical cardiac metastasized patients , we report a first case of a patient with a metastatic malignant melanoma in the heart without an identifiable primary source or additional metastasis in korea . a 59-year - old woman was admitted for cough and pleuritic chest pain with no history of malignancy or heart disease . her initial blood pressure was 110/70 mm hg , pulse rate 70 beats / min , respiratory rate 20/min , and body temperature was 36.1. jugular veins were not distended . laboratory studies , including a complete blood count , liver , and chemical profiles were in normal ranges . chest computed tomography showed a large amount of pericardial effusion and a mass in the right atrium ( ra ) ( fig . transthoracic echocardiography showed a large mass measuring 4231 mm in the ra , which did not obstruct tricuspid valve flow . effusion analysis showed a red blood cell count of 1.910/mm and a white blood cell count of 3300/mm ( lymphocytes , 55% ; neutrophils , 14% ) . cardiac mri also revealed a large mass surrounding ascending aorta spread into transverse sinus and around pulmonary trunk ( fig . considering the risk of open heart surgery and poor prognosis of extensive cardiac metastasis , pericardial window operation and epicardial mass biopsy were performed to relieve symptoms and confirm the pathological diagnosis . pathological analysis including immunohistochemistry revealed the final diagnosis to be malignant melanoma ( fig . positron emission tomography revealed no other distant organ metastasis except for heart and mediastinal lymph nodes . malignant melanoma has aggressive biological behavior and the greatest tendency for metastasis to the heart.1 ) although autopsy studies reported an incidence of 50% to 71% , cardiac metastasis is diagnosed in less than 1% of patients with malignant melanoma because less than 10% of these patients present with cardiac symptoms.2 ) such metastases most frequently occur after multifocal hematological dissemination and may develop anywhere in the heart.3 ) melanotic metastases can invade the wall of any of the 4 cardiac chambers , and the ra is involved most frequently.4 ) the clinical signs and symptoms of cardiac metastasis are unclear and non - specific , although when present , the clinical signs and symptoms include fatigue , weakness , pericardial effusion , congestive heart failure , cardiac arrhythmia , superior vena cava syndrome , right ventricular outflow and inflow obstruction , and transient ischemic attack.5 ) however , patients with malignant melanoma who have cardiac metastases may present symptoms only caused by tumors in other organ systems . although cardiac involvement occurs during the course of the disease , it is rare that the initial manifestation is cardiac metastasis . a tumor 's anatomic location and extent of invasion determine the feasibility of surgical intervention , which should optimally be performed during the early stages of the disease.6 ) a complete resection of an intracardiac melanoma prevents potential morbidities that are associated with progressive intracardiac growth , such as superior vena cava syndrome , right ventricular outflow and inflow obstruction , dysrhythmia , cardiac tamponade , and heart failure.6 ) even when total resection is not possible , conservative surgery can relieve symptoms and prevent imminent cardiac failure . conservative surgery improves the quality of a patient 's life , as in our patient 's case . although more than 90% of melanomas have a cutaneous origin,7 ) melanomas may sometimes present metastatically in the absence of a primary lesion , termed melanomas of unknown primary origin . most authors estimate that 2 - 6% of patients are diagnosed with metastatic melanoma of unknown primary site . in particular , such a metastatic melanoma in the heart such as in this patient without a known primary cutaneous origin is a rare presentation and chiefly an anecdotal finding of metastatic melanoma . several reported cases can be found in the literature about cardiac involvement with cutaneous primary malignant melanoma and multiple metastasis in korea , as well as worldwide.8)9 ) as far as we know , malignant cardiac melanoma without a primary origin has not yet been reported in korea . the survival of patients with unknown primary melanoma was demonstrated to be similar to that of patients with known primary tumors when corresponding stages were compared.10 - 12 ) those patients with metastases to any other visceral sites are described to have a 1 year survival rate of 41% and a median survival of approximately 6 months.11)13)14 ) accordingly , we expected that the outcome of this patient might be very unfavorable . although total resection was not possible because of extensive cardiac metastasis , a pericardial window operation could resolve her symptoms . after surgery , chemotherapy was planned , including cisplatin , dacarbazine , casmustine , and tamoxifen . however , the patient refused further chemotherapy after completion of two sessions . as only few reports about cardiac metastasis of malignant melanoma without cutaneous origin have been published , we are uncertain if conservative surgery is associated with prolonged survival and if the role of surgery for survival is worth further investigation .
malignant melanoma has a very high propensity to metastasize to the heart . however , melanoma may sometimes present as a metastatic lesion in the absence of a primary lesion , which are called melanomas of unknown primary origin . 
 we report a case in which a patient presented with a metastatic maligant melanoma in the right atrium with pericardial effusion and without a primary origin .