Primary primitive neuroectodermal tumor in the pericardium—a focus on imaging findings: A case report

BACKGROUND: Primitive neuroectodermal tumors (PNETs) are rare, sporadic malignant tumors of the peripheral nervous system, bone, or soft tissues. However, to the best of our knowledge, only three cases of PNET in the pericardium have been reported in the English literature, and their magnetic resonance imaging findings have not previously been described. CASE SUMMARY: A 3-year-old boy was hospitalized with a 1-wk history of recurrent vomiting and weakness. Detailed history-taking revealed no evidence of heart disease. Computed tomography demonstrated a soft tissue mass in the left pericardial cavity with heterogeneous contrast enhancement. The border between the mass and the heart was poorly defined. Thoracotomy revealed a mass invading the left ventricle, with a high risk of bleeding. The mass was considered inoperable. A biopsy was performed, and the histological and immunohistochemical findings confirmed the diagnosis of primary PNET of the pericardium. The patient received four cycles of standard chemotherapy. Chest magnetic resonance imaging 3 mo after the initiation of chemotherapy revealed that the tumor in the pericardium still existed, but its volume had slightly decreased. The patient was lost to follow-up, and the final outcome was therefore unknown. CONCLUSION: Medical imaging plays an important role in defining the pericardial origin of PNET and understanding its characteristics. Magnetic resonance imaging can provide more information on the tumor than computed tomography and may thus aid therapeutic planning.