Which of the following is not classified as a common pediatric cancer?

Adenocarcinoma is considered to be less common in pediatric populations compared to other cancer types. Pediatric cancers often include malignancies such as neuroblastoma, which arises from immature nerve cells and is one of the most common cancers diagnosed in infants and young children. Additionally, germinoma, which is a type of germ cell tumor, and various forms of sarcoma, including osteosarcoma and rhabdomyosarcoma, also frequently occur in children.

Adenocarcinomas, however, are more prevalent in adults and are associated with glandular tissues, making them an atypical and rarer classification for children. Thus, while it can occur, it does not fall within the common types seen in pediatric oncology, distinguishing it from the other options provided.