Congenital tumors are a rare diagnosis in the fetus and newborn. They differ from those of children and adults in terms of the nature, location and evolution of the tumor.

Indeed, some histologically benign tumors may have lethal potential in utero (e.g. sacrococcygeal teratomas) or even undergo malignant transformation if left untreated. In contrast, other tumors that are malignant by histological criteria may have a very good prognosis, regressing spontaneously within the first year of life (e.g. neuroblastoma).

Despite advances in imaging, benign and malignant solid tumors remain a major diagnostic and prognostic challenge in the antenatal context.

The management of congenital tumors requires multidisciplinary expertise, taking into account the perinatal context, which poses specific problems, particularly in terms of therapeutic aspects, but also the frequent existence of associated malformations and/or genetic predisposition syndromes.

This study focuses on solid tumors of the thoraco-abdomino-pelvic region, the main objective being to investigate the correlation between antenatal clinical and radiological analysis and confirmed postnatal diagnosis of congenital solid truncal tumors, as well as the developmental spectrum in which they fit.

Congenital tumors are a rare diagnosis in the fetus and newborn. Despite advances in imaging techniques, it remains a major diagnostic and prognostic challenge. The congenital tumor differs from that of the child and adult in terms of tumoral nature, localization and evolution.

The investigation of a congenital tumor must be multidisciplinary and exhaustive, since it is estimated that congenital tumors are associated with a genetic predisposition syndrome in 10% to 15% of cases, and this proportion is set to rise in the coming years.

Precise analysis of the spectrum of tumors involved, and diagnosis of the nature of the tumor, are the basis for advice and pre- and post-natal care. Prenatal information given to parents must be accurate and precise, as the diagnosis of a congenital tumor may lead to a request for medical termination of pregnancy.

Diagnostic performance in the characterization of a tumor mass in antenatal care is still imperfect.

Diagnostic performance in the characterization of a tumor mass in antenatal care is still imperfect.

By reporting on our experience in the management of congenital tumors in the Ile-de-France region, we aim to improve our understanding of the developmental spectrum in which these tumors occur. By clarifying the diagnosis, the resulting management can be optimized and adapted to each situation. The challenge is to treat the tumor effectively and sustainably, while avoiding overly aggressive treatments when they are not indicated. Post-natal therapies will be described in detail for each situation, to produce a simplified algorithm for management.

The quality of this information will condition the parents' experience and avoid requests for medical termination of pregnancy for benign tumors and/or spontaneous involution. On the contrary, this will be discussed in rare cases of very aggressive tumor involving the functional or vital prognosis of the unborn child or occurring in a context of known genetic predisposition.

Inclusion Criteria:

• Information of the holders of parental authority of the patients concerned by the research
• Malignant or benign solid tumor
• Thoracic, abdominal or pelvic location
• Clinico-radiological or histological diagnosis confirmed postnatally up to 1 year of life with onset of symptoms in the first three months of life
• Mother-child whose care course for the child's congenital axial tumor included treatment at the AP-HP

Exclusion Criteria:

• Opposition from holders of parental authority of patients
• Sacrococcygeal teratomas
• Central nervous system tumors
• Heart tumors
• Ovarian cysts
• Head and neck tumors
• Congenital leukemia and hemopathy

Mother-child whose care course for the child's congenital axial tumor included treatment at the AP-HP (Assistance Publique - Hôpitaux de Paris) between 2010 and 2021. Fetus presenting a malignant or benign solid tumor of thoracic, abdominal or pelvic location and whose clinico-radiological or histological diagnosis is confirmed postnatally up to 1 year of life with the onset of symptoms in the first three months of life.