1 Describe the underlying genetic defect in retinoblastoma. Retinoblastoma, a primitive neuroectodermal cell tumor, develops as a result of an absence of pRb, the retinoblastoma protein, which functions as a regulator of the cell cycle by modifying transcription factors, which…
1 What infectious agent plays a central role in the development of most post-transplant lymphoproliferative disorder and why? Epstein-Barr virus (EBV), a ubiquitous human herpesvirus transmitted primarily via saliva, is causally involved in most lymphoproliferative disease. Initial infection with EBV…
1 How common are childhood central nervous system tumors? Approximately 3500 cases of pediatric central nervous system (CNS) tumors are diagnosed each year in the United States with an incidence of 6.1 per 100,000. They are the most common solid…
1 Describe the epidemiology of non-Hodgkin lymphoma in children and adolescents. Non-Hodgkin lymphoma (NHL) is a heterogeneous category that includes a wide diversity of malignancies derived from lymphocytic cell origin. Although the World Health Organization (WHO) classification of lymphoid neoplasms…
1 Describe the incidence and epidemiology of Hodgkin lymphoma in children and adolescents. There are approximately 1200 new cases of Hodgkin lymphoma (HL) diagnosed in the United States annually among children and adolescents. Among adolescents, HL is associated with a…
1 What is the differential diagnosis of a child with an abdominal mass? The most likely diagnoses in a child with an abdominal mass are neuroblastoma and Wilms tumor or nephroblastoma. Clinically, children with advanced stage neuroblastoma appear ill, often…
1 What is the differential diagnosis of a liver mass in a child? Liver tumors in children are rare but mostly malignant. Differential diagnosis varies by age. In infants and toddlers, the most common malignant liver mass is hepatoblastoma (HB;…
1 What is neuroblastoma? Neuroblastoma is the most common extracranial malignant tumor of infants and children. It originates from neural crest cells that normally give rise to the adrenal gland and the sympathetic nervous system. It can have widely varying…
1 What are the most common malignant bone tumors in children, adolescents, and young adults? Malignant bone tumors account for 6% of all childhood malignancies. Osteosarcoma (OS) represents 56% of new malignant bone tumor diagnosis, followed by Ewing sarcoma (ES)…
1 What is a soft tissue sarcoma? Soft tissue sarcomas (STS) are a diverse group of malignant tumors believed to originate from developing mesenchyme, which normally give rise to components of connective tissue (muscle, bone, fat, cartilage, blood vessels). The…