eMedicine Specialties > Orthopedic Surgery > Neoplasms

Fibrous Cortical Defect

Bernardo Vargas, MD, Consulting Staff, Department of Orthopedic Surgery, Hôpital Universitaire de Geneva, Switzerland

Updated: Jun 26, 2009

Introduction

Phemister provided the first description of fibrous cortical defect (FCD) in 1929. Sontag and Pyle reported a radiologic description in 1941, and in 1942, Jaffe and Lichtenstein described clinical and anatomic aspects and the natural history.^{[1,2 ]}See radiographs below.

Plain radiograph demonstrating multiple fibrous cortical defects in multiple bones.

Plain radiograph of fibrous cortical defect of the proximal tibia.

Lateral radiograph demonstrating a solitary fibrous cortical defect in the proximal tibia.

FCD usually is an incidental finding on radiographs. Always benign, these lesions may result in pathologic fracture, although pathologic fracture is a rare first presentation.^{[5 ]}FCD can exist in multiple sites. FCD may be difficult to diagnose in the presence of pain or swelling of soft tissues. Fractures and impending fractures are indications for surgical intervention. Association with other bone lesions such as aneurysmal bone cyst is rare.^{[2,4,6,7,8,9 ]}

Problem

Fibrous cortical defect (FCD) 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.

Frequency

This 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 fibrous cortical defect (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.^{[3,10 ]}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.

Etiology

The etiology of fibrous cortical defect (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.

Pathophysiology

The average duration of fibrous cortical defect (FCD) varies from 29-52 months, followed by spontaneous resolution. FCD may be present during childhood, but lesions tend to disappear in adolescence.

Presentation

FCD is encountered frequently in children and adolescents and is usually asymptomatic.^{[3,10,11 ]} Pain is rare and, if present, is usually associated with a fracture. Fibrous cortical defect (FCD) typically is localized in long bones. The most common sites are the femur and tibia. On rare occasions, it may be encountered in the vertebrae, 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 axis of involved bone.

Indications

The characteristic location and appearance are usually suggestive of a benign lesion and are often pathognomonic for fibrous cortical defect (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:

• Does the lesion involve more than 50% of the transverse diameter of the bone? Prophylactic surgery may be indicated, as the risk of fracture is higher in this circumstance.
• Is the lesion becoming larger and more symptomatic? A more aggressive therapy may be considered.
• Is the location of the lesion particularly associated with high risk for pathologic fracture (eg, femoral neck)? Localization around the femoral neck is associated with an increased risk of pathologic fracture, producing avascular necrosis of the femoral head. Therefore, stabilization may be indicated.

In the pediatric population, casting usually is the most appropriate treatment after pathologic fracture to avoid injuring the physes during surgery.^{[3 ]}FCD may heal spontaneously 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 Anatomy

See Intraoperative details.

Contraindications

When fibrous cortical defect (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.

Workup

Imaging Studies

• Plain radiographs
  • Usually, the diagnosis can be established based on plain radiographs, as in the images below, and biopsy is not necessary.^{[12,13,14 ]}
    • 
      

      

      Plain radiograph of fibrous cortical defect of the proximal tibia.

      
      
    • 
      

      

      Lateral radiograph demonstrating a solitary fibrous cortical defect in the proximal tibia.

      
      
• The classic picture is that of an elliptical radiolucent lesion eccentrically located within the metaphyseal cortex of long bones, especially the femur. The margins are sharply demarcated, and the appearance is often septated.
• CT scan
  • CT scan should not be performed unless a strong doubt about diagnosis is present, except to confirm a pathologic fracture, as in the image below. This lesion is located eccentrically, and CT scans should depict a central lucency. CT scans may confirm a minimally displaced fracture.^{[12,13,14 ]}
    • 
      

      

      CT scan of the fibrous cortical defect shown in the plain radiographs in Images 2-3; note the cortical location and the sclerotic rim around the central lucency.

      
      
  • CT scan could help in preoperative planning for FCDs in unusual locations, such as the femoral neck.
• Bone scan
  • This study is not indicated for diagnosis. Nevertheless, in some cases, a methylene diphosphonate (MDP) technetium bone scan can help to appreciate biologic activity of the lesion.^{[12,13,14 ]}
  • Minimal increased uptake can be seen in, as in the image below. In associated fractures, this study is not useful.
    • 
      

      

      Methylene diphosphonate technetium bone scan of the fibrous cortical defect in Images 2-4; uptake is minimally increased at the site of the lesion.

      
      

Diagnostic Procedures

• Biopsy is rarely needed because radiographs typically are diagnostic.

Histologic Findings

Histologic analysis of FCD reveals a predominantly bland fibroblastic component with a few histiocytes, myofibroblast cells, and giant cells, as in the image below. 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.

Histologic section of a fibrous cortical defect demonstrating a bland fibrous stroma in the absence of nuclear atypia or mitoses; a few giant cells are scattered within the stroma.

Treatment

Medical Therapy

Casting 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 Therapy

Surgery is recommended in cases of unstable fractures or if risk of pathologic fracture is high.

Intraoperative Details

The 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 may 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-up

Following first diagnosis

Typical lesions do not require more than 1 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 involution and ossification as puberty is reached. This usually proceeds from the diaphyseal end 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.

Complications

Injury to the physis and subsequent growth abnormalities are possible adverse effects of surgery for lesions abutting a physis.

Outcome and Prognosis

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 Controversies

The etiology of FCD remains obscure (see Etiology).

Multimedia

Media file 1: Plain radiograph demonstrating multiple fibrous cortical defects in multiple bones.

Media file 2: Plain radiograph of fibrous cortical defect of the proximal tibia.

Media file 3: Lateral radiograph demonstrating a solitary fibrous cortical defect in the proximal tibia.

Media file 4: CT scan of the fibrous cortical defect shown in the plain radiographs in Images 2-3; note the cortical location and the sclerotic rim around the central lucency.

Media file 5: Methylene diphosphonate technetium bone scan of the fibrous cortical defect in Images 2-4; uptake is minimally increased at the site of the lesion.

Media file 6: Histologic section of a fibrous cortical defect demonstrating a bland fibrous stroma in the absence of nuclear atypia or mitoses; a few giant cells are scattered within the stroma.

References

1. Sontag L, Pyle S. The appearance and nature of cyst-like areas in the distal metaphyses of children. Am. J. Roentgenol. 1941;46:185-188.

2. Jaffe H., Liechtenstein L. Non-osteogenic fibroma of the bone. Am J Pathol. 1942;18:205-221.

3. Mallet JF, Rigault P, Padovani JP, Touzet P, Nezelof C. Non-ossifying fibroma in children: a surgical condition ?. Chir Pediatr. 1980;21:179-89. [Medline].

4. Arata M, Peterson H, Dahlin D. Pathological fractures through Non-Ossifying Fibromas. Review of the Mayo Clinic experience. J Bone J Surg. 1981;63A:980 - 988.

5. Sakamoto A, Tanaka K, Yoshida T, Iwamoto Y. Nonossifying fibroma accompanied by pathological fracture in a 12-year-old runner. J Orthop Sports Phys Ther. Jul 2008;38(7):434-8. [Medline].

6. Campanacci M, Laus M, Boriani S. Multiple non-ossifying fibromata with extraskeletal anomalies: a new syndrome?. J Bone J Surg. 1983;65B:627-632. [Medline].

7. Hoeffel C, Panuel M,, Plenat F, Mainard L, Hoeffel JC. Pathological fracture in non-ossifying fibroma with histological features simulating aneurysmal bone cyst. Eur Radiol. 1999;9(4):669-71. [Medline].

8. Peuchmaur M, Forest M, Tomeno B, Abelanet R. Multifocal nonosteogenic fibroma: report of a case with ultrastructural findings. Hum Pathol. Jul 1985;16(7):751-3. [Medline].

9. Skrede O. Non-osteogenic fibroma of bone. Acta Orthop Scand1970;41(4):362-80. [Medline].

10. Faure C, Laurent JM, Schmit P, Sirinelli D. Multiple and large non-ossifying fibromas in children with neurofibromatosis. Ann Radiol (Paris). 1986;29(3-4):369-73. [Medline].

11. Hetts SW, Hilchey SD, Wilson R, Franc B. Case 110: Nonossifying fibroma. Radiology. Apr 2007;243(1):288-92. [Medline].

12. Huzjan R, Vukelic-Markovic M, Brkljacic B, Ivanac G. The value of ultrasound in diagnosis and follow-up of fibrous cortical defect. Ultraschall Med. Oct 2005;26(5):420-3. [Medline].

13. Loberant N, Samovsky M, Papura S. Gray-scale and Doppler characteristics of fibrous cortical defects in a child. J Clin Ultrasound. Sep 2003;31(7):369-74. [Medline].

14. von Falck C, Rosenthal H, Gratz KF, Galanski M. Nonossifying fibroma can mimic residual lymphoma in FDG PET: additional value of combined PET/CT. Clin Nucl Med. Aug 2007;32(8):640-2. [Medline].

Keywords

fibrous cortical defect, FCD, nonosteogenic fibroma, nonossifying fibroma, metaphyseal fibrous defect, fibrous tumor, bone tumor

Contributor Information and Disclosures

Author

Bernardo Vargas, MD, Consulting Staff, Department of Orthopedic Surgery, Hôpital Universitaire de Geneva, Switzerland
Disclosure: Nothing to disclose.

Medical Editor

Howard A Chansky, MD, Associate Professor, Department of Orthopedics and Sports Medicine, University of Washington Medical Center
Howard A Chansky, MD is a member of the following medical societies: American Academy of Orthopaedic Surgeons
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Sean P Scully, MD, PhD, Professor, Department of Orthopedics, University of Miami
Sean P Scully, MD, PhD is a member of the following medical societies: American Academy of Orthopaedic Surgeons, International Society on Thrombosis and Haemostasis, and Society of Surgical Oncology
Disclosure: Nothing to disclose.

CME Editor

Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital
Dinesh Patel, MD, FACS is a member of the following medical societies: American Academy of Orthopaedic Surgeons, American Association of Physicians of Indian Origin, American College of International Physicians, and American College of Surgeons
Disclosure: Nothing to disclose.

Chief Editor

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
Harris Gellman, MD is a member of the following medical societies: American Academy of Medical Acupuncture, American Academy of Orthopaedic Surgeons, American Orthopaedic Association, American Society for Surgery of the Hand, and Arkansas Medical Society
Disclosure: Nothing to disclose.

Fibrous Cortical Defect and Nonossifying Fibroma

ACR Appropriateness Criteria® bone tumors. American College of Radiology - Medical Specialty Society.  1995 (revised 2005).  5 pages.  NGC:004783

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