Mediastinal seminoma occurring in Down syndrome

Area of Science:

• Oncology
• Genetics
• Pathology

Background:

• Down syndrome is associated with an elevated risk of certain cancers, particularly testicular germ cell tumors like seminoma.
• Primary mediastinal seminoma is rare, and its occurrence in individuals with Down syndrome has not been previously reported.

Observation:

• An anterior mediastinal tumor was incidentally discovered in a 28-year-old Japanese male with Down syndrome undergoing treatment for aplastic anemia.
• The patient was scheduled for a bone marrow transplantation.

Findings:

• Histopathological examination of the resected mediastinal tumor confirmed it to be a classic seminoma.
• This diagnosis represents the first reported instance of primary mediastinal seminoma in an individual with Down syndrome.

Implications:

• This case expands the spectrum of known cancer risks in individuals with Down syndrome.
• It highlights the importance of considering extragonadal germ cell tumors, such as mediastinal seminoma, in Down syndrome patients presenting with relevant symptoms or incidental findings.