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Journal of Clinical Oncology, Vol 22, No 6 (March 15), 2004: pp. 1153-1156 © 2004 American Society of Clinical Oncology. DOI: 10.1200/JCO.2004.04.195
Unusual Sites of Metastatic InvolvementCASE 2. Intracardiac Metastasis From a Merkel Cell CarcinomaDepartments of Internal Medicine, Cardiology, and Pathology, De Heel Zaans Medisch Centrum, Zaandam; Department of Pathology, Vrije Universiteit Medisch Centrum, Amsterdam, The Netherlands A 63-year-old woman was admitted with progressive dyspnea and chest pain. She had a history of Merkel cell carcinoma of the right leg, which had been treated surgically. Block dissection revealed a large 2.2 cm tumor mass and one (out of twelve) inguinal lymph node micrometastasis. One year after this procedure, a single skin metastasis on the right leg was removed, and 2 years later an abdominal skin metastasis was removed. Two months thereafter, the patient was admitted with pericardial and pleural effusion, for which no plausible explanation was found at that time. Medical history further revealed paroxysmal atrial fibrillation. The patient was dyspnoeic. Blood pressure was 175/93 mmHg, pulse rate 74 bpm, body temperature 36.8°C, and central venous pressure was elevated. There was no sign of pulsus paradoxus. Heart sounds were normal. Examination of the thorax showed signs of right-sided pleural effusion. There was peripheral edema. The liver was not enlarged. Electrocardiography revealed atrial fibrillation with ventricular response rate of 70 to 80/min. There were anterolateral repolarization disorders, but no signs of acute infarction. Laboratory tests showed normal blood gas-analysis, hematologic values, kidney function, electrolytes, and liver enzymes. The creatinine phosphokinase was normal, where as the lactate dehydrogenase was elevated with a value of 905 U/L (normal value, 175 to 400 U/L). A chest-radiograph showed an enlarged heart compatible with pericardial effusion and right-sided pleural effusion. Given the past history and the presence of pleural effusion, the clinical diagnosis of pericardial effusion with cardiac tamponade was made. Transesophageal ultrasound revealed a mass in the right atrium. Subsequent computed tomography demonstrated a large tumor in the heart (diameter, 10 x 15 cm), with infiltration in the right atrium and the right ventricle. The superior caval vein was severely obstructed, significantly impeding inflow in the right atrium (Fig. 1A and B). Because of metastatic malignancy and the patient's condition, the decision was made not to operate. She deteriorated rapidly and died several days later. On postmortal examination of the heart, two separate tumors were observed, situated within the right atrium with extensive transmural growth towards the epicardium. One of these tumors was located 0.5 cm proximal of the tricuspid valve. Furthermore, tumor expansion was found in the area of the aortic orifice, surrounding the aneurysmatic dilated proximal part of the aorta (Fig 2A). The right coronary artery was completely surrounded by the tumor (Fig 2B). No other distant metastases were observed.
Histologic examination demonstrated a malignancy identical with the primary cutaneous Merkel small-cell carcinoma. The tumor consisted of solid sheets of small blue cells, which showed a narrow rim of amphophyllic cytoplasm surrounding a vesicular small nucleus that contained multiple nucleoli. Mitotic figures were abundant. Immunohistochemical staining was positive for the epithelial markers CAM5.2, EMA, and Cytokeratin 20. With CAM5.2, a characteristic paranuclear granular staining pattern was found. Cytokeratin 20 was positive, a valuable discriminant from other types of small-cell carcinoma. The neuro-endocrine features were detected by positive staining for neuron-specific enolase, chromogranin A, and synaptophysin (Fig 3). The S100, Melan-A, and LCA staining were negative. This immunohistochemical staining pattern is characteristic of a Merkel cell carcinoma.
Metastatic disease to the heart is a rare finding at autopsy in an unselected group of patients [1,2]. However, large autopsy studies showed intracardiac metastases in approximately 15% of patients with disseminated cancer [3]. Remarkably, these metastases are asymptomatic in the majority of cases. Tumors with a high tendency of metastasis to the heart are: malignant melanoma, leukemia [4], malignant germ cell tumors, and malignant thymoma [3]. Although carcinoma of the lung and breast do not metastasize to the heart frequently, because of the high incidence of these tumors, they account for the greatest numbers of cardiac metastases. Intracardiac metastases are more often located within the right side of the heart [3,5]. The most common clinical manifestations result from pericardial effusion, tachy-arrhythmias, atrioventricular block, and congestive heart failure. Furthermore, symptoms arising from obstruction of the superior vena cava can be observed [5]. Occlusion of a coronary artery with or without tumor embolus may result in ischemia [3]. Atrial arrhythmias may occur secondary to neoplastic involvement of autonomic fibers supplying the atria. Other causes are invasion by tumor of the coronary vessels with atrial infarction and neoplastic infiltration of the sinus node or atrial myocardium [5], as was the case in our patient. Merkel cell carcinoma is a rare, aggressive small-cell tumor of the skin with neuro-endocrine differentiation. The overall recurrence rate ranges between 55% and 79%, most often locally or in regional lymph nodes [6]. Forty percent of cases will have distant metastasis, usually to the lungs, liver, bones, meninges, and brain [7]. Metastasis to other sites, including bladder and spinal cord, have also been described [8,9]. To the best of our knowledge, this is the first report that describes a well-documented case of intracardiac metastasis of a Merkel cell carcinoma. A case of a Merkel cell carcinoma in a 23-year-old pregnant woman, who developed a mass in the right ventricle, was reported in 1990 [8]. Although there was strong suggestion of intracardiac metastasis, there was no histologic confirmation [8]. A report of a case of intracardiac metastasis in a 72-year-old patient, presenting with an acute coronary syndrome, was described in 1995 [10]. Diagnosis was confirmed using computed tomography scanning, but again no histologic examination was performed [10]. There are no randomized trials regarding therapy of Merkel cell carcinoma, probably because of its rarity [11,12]. Generally, local treatment with surgery is performed. Adjuvant radiotherapy to regional nodes is usually applied. Distant metastasis may respond temporarily to chemotherapy, such as the treatment used in small-cell carcinoma of the lung [2]. Authors' Disclosures of Potential Conflicts of Interest The authors indicated no potential conflicts of interest.
REFERENCES 1. Gollard R, Weber R, Kosty MP, et al: Merkel cell carcinoma: Review of 22 cases with surgical, pathologic, and therapeutic considerations. Cancer 88:1842-1851, 2000[CrossRef][Medline] 2. Majano-Lainez RA: Cardiac tumors: A current clinical and pathological perspective. Crit Rev Oncog 8:293-303, 1997[Medline] 3. Burke A, Virmani R: Tumors metastatic to the heart and pericardium, in Rosai J (ed): Atlas of tumor pathology. Washington, DC, Armed Forces Institute of Pathology, 1996, pp 195-209 4. Fiala W, Schneider J: Heart metastasis of malignant tumors. An autopsy study. Schweiz Med Wochenschr 112:1497-1501, 1982[Medline] 5. Braunwald E: Heart disease—A textbook of cardiovascular medicine (6th ed). Philadelphia, PA, W.B. Saunders Company, 2001, pp 1686-1689
6. Goessling W, McKee PH, Mayer RJ: Merkel cell carcinoma. J Clin Oncol 20:588-598, 2002 7. Murphy G, Elder D: Neural proliferations and neoplasia, in Rosai J (ed): Atlas of tumor pathology. Washington, DC, Armed Forces Institute of Pathology, 1991, pp 248-251 8. Chao TC, Park JM, Rhee H, et al: Merkel cell tumor of the back detected during pregnancy. Plast Reconstr Surg 86:347-351, 1990[Medline] 9. Woo HH, Kencian JD: Metastatic merkel cell tumour to the bladder. Int Urol Nephrol 27:301-305, 1995[Medline] 10. Page E, Fric D, Barjhoux JL, et al: Cardiac metastasis from a Merkel cell skin carcinoma. A case report. Arch Mal Coeur Vaiss 94:1423-1426, 2001[Medline] 11. Bourne RG, O'Rourke MG: Management of Merkel cell tumour. Aust N Z J Surg 58:971-974, 1988[Medline]
12. Tai PT, Yu E, Winquist E, et al: Chemotherapy in neuroendocrine/Merkel cell carcinoma of the skin: Case series and review of 204 cases. J Clin Oncol 18:2493-2499, 2000
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Copyright © 2004 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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