The National Institutes of Health defines adolescents and young adults as the individuals in the age group of 15-40 years old.
Even though multidisciplinary care and research have improved survival of patients with malignant bone,
several studies have revealed that survival in this age group of patients is significantly lower than that in patients younger than 15 years and older than 50 years,
specifically for bone tumors.
The reasons for these survival differences are not well understood and remain object of research.
Epidemiology
Malignant bone tumors represent 6% of all cancers in children younger than 15 years,
3% of all cancers in those aged 15-29 years and only 1% for those aged 30-50 years.
Osteosarcoma,
Ewing sarcoma,
chondrosarcoma and primary bone lymphoma are the more frequent malignant bone tumors in this age group and most present as high-grade tumors.
Ewing sarcoma has an approximately equal incidence in those aged 5-25 years with a decline after that.
Osteosarcoma is bimodal with a peak in the adolescent and another in the sixth decade.
Chondrosarcoma and primary bone lymphoma increase progressively with age.
There is as light male predominance for all primary bone tumors and no ethnic predilection except for Ewing sarcoma,
which is less common in Hispanics and is rare in African and Asian patients.
Etiology
There are no known causes for most bone tumors,
with the exception of osteosarcoma: in up to 5% of cases,
is associated with familial retinoblastoma and Li-Fraumeni,
Rothmund-Thomson and Werner syndromes.
In patients younger than 50 years,
secondary osteosarcoma may rarely be seen with Paget disease, chronic osteomylitis,
prior radiotherapy,
bone infarct,
fibrous dysplasia or dedifferentiation of giant cell tumors of bone.
Clinical presentation
Pain is the most common presenting symptom followed by an enlarging soft tissue mass and pathologic fracture.
Occasionally,
there are systemic signs such as weight loss,
fatigue, anorexia,
fevers,
or night sweats,
particularly in cases of lymphoma or Ewing's sarcoma.
After clinical presentation,
conventional radiography is the mainstay to distinguish benign from malignant lesions.
When assessing a bone lesion on a plain radiograph,
it is fundamental to analyze the zone of transition,
cortical destruction,
axis of the lesion and periostitis.
An accurate differential diagnosis can usually be made based on plain film findings and correlation with age group and localization of the lesion.
MRI and CT are then usually performed for characterizing the extent of tumor and metastases.
Metastases usually occur to the lung,
other bones and rarely to the viscera.
Lymph node spread is not uncommon.