You are in: eMedicine Specialties > Orthopedic Surgery > NEOPLASMS Fibrous Cortical DefectArticle Last Updated: Jan 28, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Bernardo Vargas-Barreto, MD, Consulting Staff, Department of Orthopedic Surgery, Centre Hospitalier Universitaire de Lausanne, Suisse Coauthor(s): Mark Clayer, MD, MBBS, FRACS, FAOrthA, Head of Musculoskeletal Tumor Service, Queen Elizabeth Hospital; Senior Visiting Medical Specialist, Department of Orthopaedics and Trauma, Royal Adelaide Hospital and Women's and Children's Hospital Editors: Howard A Chansky, MD, Associate Professor, Department of Orthopedics and Sports Medicine, University of Washington Medical Center; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Sean P Scully, MD, PhD, Professor, Department of Orthopedics, University of Miami; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; Harris Gellman, MD, Consulting Surgeon, Broward Hand Center, Voluntary Clinical Professor of Orthopedic Surgery and Plastic Surgery, Departments of Orthopedic Surgery and Surgery, University of Miami School of Medicine Author and Editor Disclosure Synonyms and related keywords: FCD, nonosteogenic fibroma, nonossifying fibroma, metaphyseal fibrous defect, fibrous tumor, bone tumor INTRODUCTIONSection 2 of 12
  Phemister provided the first description of fibrous cortical defect (FCD) in 1929. Sontag and Pyle reported a radiologic description in 1941,1 and in 1942, Jaffe and Lichtenstein described clinical and anatomic aspects and the natural history.2 Also called nonossifying or nonosteogenic fibroma, this benign tumor probably is the most frequent bony lesion in children, occurring in up to 30-40% of children.3 The condition is most common in adolescents. Fibrous cortical defect is a term coined to describe the smaller variety of nonossifying fibromas.4 However, no histologic difference exists between the lesions. When the lesion is large enough to encroach upon the medullary canal, the term nonossifying fibroma (NOF) is used. In this article, the terms FCD and NOF are interchangeable. The authors believe that these should be considered the same entity. These lesions are, in fact, developmental abnormalities as opposed to benign neoplasms. FCD usually is an incidental finding on radiographs. Pathologic fracture is a rare first presentation. FCD can exist in multiple sites (see Image 1). FCD may be difficult to diagnose in the presence of pain or swelling of soft tissues. Always benign, these lesions may result in pathologic fracture. Fractures and impending fractures are the indications for surgical intervention. Association with other bone lesions such as aneurysmal bone cyst is rare.2, 4, 5, 6, 7, 8 ProblemFCD may present with a pathologic fracture, but this is an unusual presentation. FCD also can be confused with a more aggressive lesion. Therefore, biopsy may be necessary. FrequencyThis lesion constitutes 5% of benign tumoral lesions of bone. The true incidence is more likely to be on the order of 30% or more, but because FCD is asymptomatic in most patients, most lesions are never identified. Sontag and Pyle identified this lesion in 54% of boys and 22% of girls in a series of 200 healthy children.3, 9 These lesions occur in multiple sites in approximately 50% of patients. This lesion is rare in children younger than 2 years and is most common in adolescents. EtiologyThe etiology of FCD remains obscure. FCD is a proliferation of benign fibrous tissue, possibly as a result of periosteal injury or secondary to abnormalities at the epiphyseal plate. Others postulate that FCD is related to the normal cutback phenomenon seen in maturing physeal plates. Progression of this lesion introduces abnormal tissue into the metaphyseal cortex. PathophysiologyThe average duration of FCD varies from 29-52 months, followed by spontaneous resolution. FCD may be present during childhood, but lesions tend to disappear in adolescence. ClinicalFCD is encountered frequently in children and adolescents and is usually asymptomatic.3, 9 Pain is rare and, if present, is usually associated with a fracture. FCD is typically localized in long bones. The most common sites are the femur and tibia. On rare occasions, it may be encountered in the vertebra, clavicle, or bones of the upper limbs. The association of multiple FCDs with café au lait spots, multiple nevi, mental retardation, hypogonadism, and ocular and cardiovascular abnormalities is called Jaffe-Campanacci syndrome. FCD lesions have a typical and relatively distinct radiographic appearance. The lesion is radiolucent and is located eccentrically, usually in the distal metaphysis of a long bone. The cortex is thin, with sclerotic or scalloped margins. Lesions can be uniloculated or multiloculated. The longitudinal axis of FCD tends to be parallel to the involved bone. INDICATIONSSection 3 of 12
The characteristic location and appearance are usually suggestive of a benign lesion and are often pathognomonic for FCD; thus, no further action is necessary unless a pathologic fracture has occurred or risk of fracture is high. The following considerations should be kept in mind:
In the pediatric population, casting usually is the most appropriate treatment after pathologic fracture to avoid injuring the physes during surgery.3 FCD may spontaneously heal following fracture. If, after casting and union of the fracture, the lesion does not regress, curettage and grafting are indicated. In unstable fractures or in adolescents, curettage (with or without grafting) and internal fixation are appropriate. RELEVANT ANATOMYSection 4 of 12
CONTRAINDICATIONSSection 5 of 12
When FCD is near an open physis, surgery should be avoided if possible. With time, the FCD will migrate away from the physis, and risk of damage to the growth plate will be minimized. WORKUPSection 6 of 12
Imaging Studies
Diagnostic Procedures
Histologic FindingsHistologic analysis of FCD reveals a predominantly bland fibroblastic component with a few histiocytes, myofibroblast cells, and giant cells (see Image 6). The lesion is marked by proliferations of spindle cells arranged in a storiform pattern. Hemosiderin deposits also are found. Around the lesion, some leukocyte infiltration may be present. Fractures through an FCD may change the histologic pattern. In these cases, the presence of blood deposits due to the fracture and formation of new bone are seen. Care must be taken not to confuse early callous with osteogenic sarcoma. TREATMENTSection 7 of 12
Medical therapyCasting usually is the most appropriate treatment after pathologic fracture in pediatric patients to avoid injuring the physes during surgery. If the lesion does not regress after casting and union of the fracture, curettage and grafting are necessary. Surgical therapySurgery is recommended in cases of unstable fractures or if risk of pathologic fracture is high. Intraoperative detailsThe surgical approach involves exposing the fracture site and developing a cortical window to curette the tumor. The lesional tissue is gray or brown-yellow. The texture is firm. Bone septa could be present, giving the impression of a multicameral lesion. As mentioned previously, surgery should be delayed, if possible, for lesions abutting a physis. Corticancellous allograft (author's preference) or autograft can be used, depending upon the size of the lesion. Follow-upFollowing first diagnosis Typical lesions do not require more than one follow-up examination and radiograph (after a 6-12 week interval). Large lesions must be followed with plain films every 4-6 months to assess progression. The lesion may increase in size. A lesion that measures more than 50% of the transverse diameter of the bone is susceptible to pathologic fracture. Patients must be instructed to avoid excessive activities in order to prevent acute fractures. Contact sports also must be avoided. The natural history of NOF is for involution and ossification as puberty is reached. This usually proceeds from the diaphyseal to the metaphyseal end of the lesion. Following fracture Immobilization following fracture is continued until union is radiologically evident. At this point, if the lesion is not regressing and is at risk for refracture, curettage with or without internal fixation and grafting may be indicated. COMPLICATIONSSection 8 of 12
Injury to the physis and subsequent growth abnormalities are possible adverse effects of surgery for lesions abutting a physis. OUTCOME AND PROGNOSISSection 9 of 12
The rarity of FCDs in adults confirms that these lesions regress with time. The prognosis is excellent in the unusual cases in which patients require curettage and bone graft. FUTURE AND CONTROVERSIESSection 10 of 12
The etiology of FCD remains obscure (see Etiology). MULTIMEDIASection 11 of 12
REFERENCESSection 12 of 12
Fibrous Cortical Defect excerpt Article Last Updated: Jan 28, 2008 | |||||||||||||||||||||||||||||||||||||||||||||||
