Nonossifying fibroma (NOF) (synonyms: nonossifying bone fibroma; nonosteogenic fibroma; fibrous cortical defect; fibrous cortical defect; fibroxanthoma; cortical fibroma; medullary fibroma; metaphyseal defect; benign cortical defect; benign histiocytic fibroma; histiocystic xanthogranulum; ICD-10 D16. -: Benign neoplasm of bone and articular cartilage) refers to a benign (benign) tumor-like lesion of bone (“tumor-like lesions”; tumor-like mass) caused by a disturbance in the development and mineralization of growing bone. In this developmental abnormality, part of the bone is filled with connective tissue instead of bone tissue.
A fibrous cortical defect is distinguished from a non-ossifying fibroma, which is smaller and limited to the cortical bone (outer layer of bone). Once the process extends into the bone, it is referred to as a non-ossifying fibroma. Both forms represent the most common fibrous lesion of bone.
As a rule, non-osseous fibroma occurs solitarily (singly), but it can also occur multiply (8% of cases). Then the occurrence is associated with neurofibromatosis (Jaffé-Campanacci syndrome; growing osteofibrous lesion of the tibia/tibia with deformation of the bone).
Sex ratio: boys/men to girls/women is 2: 1.
Peak incidence: non-osseous fibroma (NOF) occurs predominantly between the ages of 10 and 20.
Fibrous cortical defects occur in approximately 30% of young adults.
Course and prognosis: Non-osseous fibroma is almost always clinically silent and heals by ossification (ossification) over the years in the course of bone development without consequences (spontaneous remission), so that surgery is not necessary even for larger lesions. Even if a fracture (bone break) occurs due to the non-ossifying fibroma (very rare), surgery is not mandatory, since the fracture itself is a stimulus for ossification. The prognosis is very good.
