This Issue's Rounds Question (responses to be published in next issue)
Are Latex Gloves a danger for allergenic patients? Could they potentially cause an anaphylactic reaction?

In the last issue of Body Cast, Rounds asked: “A youth is in the emergency department with an ankle injury. An x-ray of the tibia is performed, and a fibrous cortical defect is observed on the tibia. The parents are concerned. Tell us about the non-ossifying fibroma.”

The following responses were received:

From Kimberly Leslie:

The cause of non-ossifying fibroma is the failure of a nest of fibrous tissue to calcify. The source of this condition is most likely a developmental defect. It is extremely common in the general population and can be found in as many as 30 to 50% of children over the age of two. It is usually found in long bones, and is most common in the lower limbs. It arises in the metaphysic of the bone. Non-ossifying fibromas are composed of benign fibroblasts and sometimes macrophages. Patients usually have no symptoms and the fibroma is often found accidentally. It appears as a demarcated lucent area in the bone. In most cases, treatment is not necessary because healing occurs spontaneously over a period of several years. The condition is not a genuine bone tumour.

From Brian Lavallee:

Benign non-ossifying fibromas are common small asymptomatic lesions made up of swirled bundles of connective tissue within the bone cortex. Pathologically, it is believed that these lesions are due to unrecognized trauma to the periosteum, causing hemorrhage and edema.

Typically, these lesions are incidental findings in healthy children, and they usually occur at the sites of muscle attachment, and then migrate into the diaphysis as the bone grows. They are rare in children under the age of two and rare in adults, implying that they are due to muscle-pull injuries in weight-bearing activities such as walking, and that they are replaces by healthy bone as the child matures. These lesions are most commonly found on the tibia or femur, and involvement of the bones of the upper limbs is uncommon.

Radiographically, these lesions are circular or oval and have a clear border with a narrow, sharply defined sclerotic (white) border. Often, these lesions are multilochular with internal septae. Significantly, there is no periosteal or soft tissue reaction to the lesion. Because of these clear presenting traits, these lesions can be positively identified on plain film x-rays and other lesions can be ruled out. For instance, aggressive malignancies tend to have less well-defined borders, and more periosteal reactions, resulting in a large, less sharply defined transition zone between the lesion and normal bone.

From Mary Perkins:

A non-ossifying fibroma is a non-aggressive, benign cortical defect which is usually found in the metaphysic of any long bones such as the femur or tibia. It is a common bone lesion that results from a defect of periosteal cortical bone development that leads to a failure of ossification. Thirty to 40% of children over the age of two have one or more lesions, but it is most common between eight and 20 years of age. The lesion usually is asymptomatic and may go undetected until a pathological fracture occurs. Healing occurs spontaneously over a period of years. Treatment of the acute fracture would be immobilization with casting, but if the lesion is exceptionally large, then curettage and bone grafting may be required.

From Bert Sheppard and Cam Longphee:

Non-ossifying fibroma is known as fibroma of the bone or cortical defect. It is probably the most common lesion of the bone. Up to 40% of children have this lesion. A lot of times, this lesion is found accidentally by x-rays. The patient has no abnormal physical findings.

Patients who present with a non-ossifying fibroma that is more than 50% of the diameter of the bone should have the lesion corrected and packed with bone grats. Some go on to get pathological fractures which heal without any difficulty.

Non-ossifying fibroma should be recognized based on clinical presentations and plain x-rays. They do not require treatment, but should be observed between three- and six-month intervals with x-rays.

Responses were also reveived from L. Arseneau, T. Broughton, E. Clancey, A. Crossman, N. Ellsworth, P. Gaudet, M. Gillingham, R. Grenier, D. Lundrigan, L. Macdonald, G. Marshall, B. Matheson, J. Lalucci, I. Mills, J. Movasseli, E. Oborowsky, C. Rivers, V. Robichaud, A. Wentzell, H. Wong, N. Yao and M. Young