An occult intrapericardial yolk sac tumor occurred in a 3-year-old girl with a fatal outcome. At autopsy, a 5.5-cm mass surrounded the base of the heart and compressed the left atrium posteriorly. Histologically, the tumor was a pure yolk sac tumor. Postmortem chemical analyses of the blood revealed an alpha-fetoprotein level greater than 7000 (mu)g/L. Acute myocarditis of both ventricles was also found.
Volk sac tumor (YST) is a rare and highly malignant neoplasm. Histologically, 10 patterns are described: microcystic, endodermal sinus, papillary, glandular-alveolar, solid, myxomatous, macrocystic, polyvesicular vitelline, hepatoid, and enteric.1 Pure YST is most commonly found in the testis during the first 2 years of life and is often curable with surgery.2 Though germ cell tumors are most often found in the gonads, extragonadal sites are documented in approximately 20% of cases.3 An intrapericardial pure YST, however, is rare, and its association with acute myocarditis is unusual.
REPORT OF A CASE
A 3-year-old girl with no significant medical history presented with a 5-day history of abdominal discomfort, increasing fatigue, lethargy, and respiratory distress. Emergency department evaluation revealed tachypnea, a pulsus paradoxus, and hepatosplenomegaly. A chest radiograph showed a widened mediastinum, cardiomegaly, and bilateral pleural effusions. The patient was transferred to our institution for further evaluation and treatment. An echocardiogram demonstrated a large pericardial effusion, poor left ventricular function and a large intrapericardial mass compressing the right atrium, left atrium, right pulmonary artery, and superior vena cava.
Subsequently, 200 mL of serosanguinous fluid was drained during pericardiocentesis. Seven hours later, the patient became acutely hypotensive and bradycardic with low oxygen saturation. An echocardiogram showed little residual pericardial fluid and severely depressed left ventricular function. Despite aggressive advanced cardiac life support, the patient became asystolic and died.
At autopsy we found a 5.5-cm, round, tan-yellow mass surrounding the base of the heart and great vessels and compressing the left atrium posteriorly. The cut surface showed central areas of hemorrhage, necrosis, and a mucoid appearance (Figure 1). The parietal pericardium was studded with small tumor nodules. Multiple tumor feeder vessels arose from the left circumflex coronary artery.
Histologically, the neoplasm was a pure YST with variable patterns. The predominant pattern was lacelike and reticular with Schiller-Duvall bodies (Figure 2, A and B) and hyaline globules. The tumor cells were atypical and pleomorphic, with nuclear vacuoles and prominent nucleoli. The mitotic activity averaged 5 per 10 high-power fields. Metastases were present in the intrapericardial lymph nodes, adventitia of the right internal carotid artery, proximal descending aorta, and lymphatics of the left subclavian artery and ascending aorta. Immunohistochemical stains for alpha-fetoprotein and a-antitrypsin were strongly positive. Additionally, foci of acute myocarditis involved both ventricles (Figure 3). Postmortem chemical analyses of the blood revealed an a-fetoprotein level greater than 7000 (mu)g/L.
Yolk sac tumor is one histologic type of germ cell tumor including seminoma, embryonal carcinoma, choriocarcinoma, and teratoma. First described by Teilum in 1959,4 its origin is believed to be from extraembryonic mesoderm and endoderm. Because it occurs almost exclusively in children, pure YST is usually easily diagnosed.
The predilection of extragonadal germ cell tumors to the midline has been attributed to the midline migratory route of germ cells from the yolk sac to the genital ridge.5 To our knowledge, 2 cases of intrapericardial YST have been documented in the English literature.5,6 We believe this report describes the only case of fatal intrapericardial YST associated with acute myocarditis.
The location of intrapericardial tumors plays an important role in the clinical presentation. Most patients present with respiratory distress, cardiac compression, and a pericardial effusion. The differential diagnosis includes anterior mediastinal tumors, thymic enlargement, and primary heart tumors. Including intrapericardial YST is important because of its rapid course and fatal outcome. In our case, acute myocarditis contributed to the patient's rapid demise; however, its etiology is unclear. It may have resulted from a reaction to adjacent tumor in the pericardial sac of may be indirectly related to an evoked immune response to the tumor.
1. Talerman A. Germ cell tumors. Curr Top Pathol. 1992;85:165-202.
2. Young RH, Scully RE. Testicular Tumors. Chicago, III: ASCP Press; 1990:3787.
3. Truong LD, Harris L, Mattioli C, et al. Endodermal sinus tumor of the mediastinum. Cancer 1986;58:730-739.
4. Teilum G. Endodermal sinus tumors of the ovary and testis. Cancer. 1959; 12:1092-1105.
5. Nelson E, Stenzel P. Intrapericardial yolk sac tumor in an infant girl. Cancer 1987;60:1567-1569.
6. Bath LE, Walayat M, Mankad P, Godman MJ, Wallace WH. Stage IV malignant intrapericardial germ cell tumor: a case report. Pediatr Hematol Oncol. 1 997;1 4:451-455.
Marie C. Sicari, MD; Billie Fyfe, MD; Ira Parness, MD; Anthony Rossi, MD; Pamela Unger, MD
Accepted for publication October 5, 1998.
From the Departments of Pathology (Drs Sicari, Fyfe, and Unger) and Pediatric Cardiology (Drs Parness and Rossi), Mount Sinai Medical Center, New York, NY; and Department of Pathology, Allegheny University Hospitals, Philadelphia, Pa (Dr Fyfe).
Reprints: Pamela Unger, MD, Mount Sinai School of Medicine, One Gustave Levy Pl, Box 1194, New York, NY 10029.
Copyright College of American Pathologists Mar 1999
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