Around 20% of healthy children may possess benign tumours, according to a review of radiographs taken nearly a century ago.
Although it sounds alarming, non-ossifying fibromas and other common benign bone tumours in symptom-free children are not dangerous. Such bone tumours are often discovered on x-rays taken for other causes, such as a fracture.
“Understandably, these tumours cause a lot of anxiety for patients and families as they await confirmation that the tumour is benign,” said Christopher Collier, MD, Indiana University School of Medicine, Indiana University. “They need reassurance and often ask how common these tumours are, when did they first appear, and whether they will resolve over time? We don’t have much evidence to date to address these questions.”
To address these questions, the researchers analysed annual x-rays taken of children’s bones as they grew, however such studies today are not feasible today due to ethical concerns over sensitivity of children to ionising radiation. Therefore, they drew on a unique collection of radiographs from the Brush Inquiry, a study in which a series of healthy, ‘normal’ children in Ohio, underwent annual radiographs from 1926 to 1942.
Dr Collier’s team analysed a total of 25 555 digitised radiographs of 262 children, followed from infancy to adolescence, finding a high prevalence of bone tumours. A total of 35 benign bone tumors were found in 33 children – an overall rate of 18.9 percent when considering that only the left side of the children was radiographed.
Over half of the tumours were non-ossifying fibromas, which are connective tissue masses that have not hardened into bone. Generally, these fibromas appeared around age five, and again around the time of skeletal maturation, possibly linked to growth spurts. Of 19 non-ossifying fibromas detected, seven disappeared over time. Others may have resolved some time after the annual radiographs stopped.
Rarer benign bone tumoors included enostoses, sometimes called ‘bone islands’; and osteochondromas or enchondromas (tumours in cartilage). In patients with these tumours, they persisted to the last available radiograph.
The findings are similar to the rates of benign bone tumours in healthy adults. Dr Collier noted: “Despite the inherent limitations of our historical study, it may provide the best available evidence regarding the natural history of asymptomatic benign childhood bone tumors.”