Type II pleuropulmonary blastoma in a fetus: case report of a rare mesenchymal mediastinal tumor and literature review.

Mediastinal tumors are exceedingly rare during fetal development, presenting significant diagnostic challenges and potentially leading to severe outcomes such as stillbirth or metastatic disease if not promptly identified and managed. Pleuropulmonary blastomas are primitive mesenchymal tumors often linked to mutations in the DICER1 gene, indicating a hereditary pattern associated with other common adult neoplasms with dominant inheritance. This report describes a case involving a 20-year-old Caucasian woman whose pregnancy was complicated by a stillbirth in the second trimester. Initial suspicions of a mediastinal tumor arose from blood tests and ultrasound examinations during pregnancy surveillance. However, the definitive diagnosis of a type II pleuropulmonary blastoma was established through a pathological examination at autopsy. This case underscores the complexities of diagnosing fetal mediastinal tumors and contributes to the sparse literature on neonatal pleuropulmonary blastomas. Our comprehensive review of the differential diagnoses and literature emphasizes the unique characteristics of pleuropulmonary blastoma and its similarities to other soft tissue sarcomas, enhancing understanding of their clinical and genetic profiles.