Prenatal diagnosis and surgical management of a neonatal mediastinal teratoma: A case report

Abstract

Abstract

ABSTRACT INTRODUCTION Antenatally diagnosed mediastinal teratomas are rare neonatal tumours that may cause significant cardiopulmonary compromise because of their location and mass effect. Prenatal detection facilitates planned postnatal evaluation and timely surgical management. CASE PRESENTATION A male fetus was diagnosed at 32 weeks' gestation with a cystic retrosternal anterior mediastinal lesion on routine obstetric ultrasonography. There was no polyhydramnios, fetal hydrops, or associated congenital anomaly, and the fetus remained haemodynamically stable without evidence of airway or cardiovascular compromise. The pregnancy was managed expectantly without fetal intervention. A 3.2-kg appropriate-for-gestational-age male infant was delivered vaginally at 37 weeks' gestation and remained asymptomatic without respiratory compromise. Postnatal chest radiography and contrast-enhanced computed tomography demonstrated a 6.5 × 4.1 × 4 cm heterogeneous anterior mediastinal mass with predominantly cystic components and focal soft-tissue attenuation, compressing the heart and adjacent right lung without radiological evidence of invasion. Serum alpha-fetoprotein and beta-human chorionic gonadotropin levels were appropriate for age. Complete excision was performed on day 8 of life through a right posterolateral thoracotomy. Intraoperatively, the encapsulated tumour occupied the anterior mediastinum and was adherent to the thymus without invasion of adjacent mediastinal structures. It was dissected free and removed en bloc with an intact capsule, without rupture or tumour spillage. Histopathological examination demonstrated a Grade III immature teratoma with clear surgical margins. In view of complete excision, the absence of malignant germ cell components or residual disease, and age-appropriate tumour marker levels, the multidisciplinary tumour board recommended surveillance without adjuvant chemotherapy. At 8 months of follow-up, the infant was thriving, with no clinical, biochemical, or radiological evidence of recurrence. CONCLUSION Early prenatal detection and complete surgical excision may enable favourable outcomes with surveillance alone, even in neonatal Grade III mediastinal immature teratomas.