What are the symptoms of non-ossifying fibroma?

Non-ossifying fibroma is most common in children and adolescents, and is most common in those aged 5 to 20 years. The incidence of non-ossifying fibroma is not high, accounting for 0.81% of the total number of tumors and 1.45% of benign tumors. The male-to-female ratio is 1.38:1, and the age is mostly between 11 and 20 years old (29.6%). It is most common in the lower limbs, femur and tibia, followed by the humerus and jaw.

The most common site of disease is the long bones of the lower limbs, mainly around the knee joint. The most common site is the distal femoral metaphysis, followed by the proximal and distal tibia metaphysis, and the proximal fibula metaphysis. Less common sites include the proximal femoral metaphysis and upper limb bones. Single non-ossifying fibroma is very rare in short bones and flat bones.

Non-ossifying fibroma can also have multiple lesions, which can occur in different parts of the same bone or in different bones. This is called multiple non-ossifying fibroma, and the age of onset is similar to that of single lesions. Multiple lesions are most common in one or both lower limbs and can also affect the pelvic bones.

The lesions are mostly in the epiphysis, and as the disease progresses, the lesions can gradually migrate to the shaft, mostly located in the cortex or under the periosteum on one side. Further development of the lesions can invade the medullary cavity, causing lesions in the entire epiphysis or shaft.

Non-ossifying fibromas are usually asymptomatic, with mild pain occasionally being the main symptom. Foreign literature reports that 50% of patients are initially diagnosed with pain, 16% are diagnosed with pathological fractures, and 32% are discovered accidentally on X-rays.

Multiple non-ossifying fibromas may be accompanied by café-au-lait spots, intellectual disability, gonadal dysfunction, congenital eye abnormalities, or vascular malformations without the neurofibromatosis syndrome, which is called the Jaffe-Campanacci syndrome.