Special section Rare tumors
Definition
Generally all malignant tumors in children and adolescents are rare diseases with an annual incidence of less than 5/100 000 . This is the reason that definition of rare pediatric solid tumors is almost always difficult.
North American the Children's Oncology Group (COG) and TREP (Tumor Rari in Eta Pediatrica) group of rare pediatric tumors therefore used for their definition not only numerical ratings (incidence of less than 2/1 million), but defines pediatric rare tumors in the context of child and the young population as tumors usually classified as epithelial (group XI of the XI International Classification of childhood cancers - ICCC) with their typical occurrence in adulthood. These tumors have in common an extremely low incidence in children under 5 years of age ( so called ultra-orphan diseases) and 75 % of them occur in adolescents (15-19 years). For most of pediatric rare tumors do not exist age specific pediatric treatment guidelines and protocols.
Due to limited experiences and literature data regarding proper and effective treatment of rare pediatric tumors it is very difficult for the attending physician as well as for the family to decide properly regarding further management. Optimal treatment in usually unknown and all informations are based only on small groups of patients, or several published case reports
Classification of rare pediatric tumors could be based on different criteria:
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Classification based on the age of child
- Tumors typical for adult age (mostly carcinomas) – account about 2% in children up to 15 years of the age and less than 10 % in adolescent age. The most frequent types of carcinomas are thyroid carcinoma, adrfenocortical carcinoma, hepatocellular carcinoma or renal carcinoma
- Typical pediatric rare tumors – extremly rare pediatric tumors occurs exclusively in children ( pancreatoblastoma, malignant rhabdoid tumor, pleuropulmonary blastoma etc.)
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Classification based on anatomic localisation and origin of the tumor
- Head and neck tumors
- Pulmonary and chest wall tumors
- Abdominal and retroperitoneal tumor
- Tumors of the small pelvis
- Tumors of the skin, extremities and others
Author: Viera Bajciova, MD, PhD