Aneurysmal Bone Cyst

Definition

Cystic lesion of bone most common in the vertebrae, flat bones and shaft of long bones delimited by fibroblasts, myofibroblasts and histiocytes. Identical lesions can occur adjacent to chondroblastoma, osteoblastoma, giant cell tumor, metaphyseal fibrous defect, fibrous dysplasia and chondrosarcoma.

Clinical Features

Usually 10–20 years of age1,2
Slightly more common in females 3
Location:
- mainly:
  - vertebrae:
    - frequently multiple involvement
  - flat bones
- also:
  - shaft of long bones4,5
- exceptionally:
  - within wall of a major artery 6–8
- Exceptionally rarely malignant transformation into osteosarcoma

Pathogenesis

Elusive
Occasionally:
- preceding trauma with fracture or subperiosteal hematoma 9
- preexisting bone lesion as result of changed hemodynamics10–12
Usually no underlying lesion:13,14
- might be result of sampling or cyst destruction of preexisting lesion
Insulin-like growth factor-1:
- may play role 15
Nonrandom cytogenetic aberrations suggest that some are true neoplasms16

Gross Pathology

Spongy hemorrhagic mass (Fig. 1
Fig. 1: Aneurysmal bone cyst of lower end of ulna. The large blood-filled cavities expand the metaphysis. (Courtesy of Dr RA Cooke, Brisbane, Australia; from Cooke RA, Stewart B: Colour Atlas of Anatomical Pathology. Edinburgh, Churchill Livingstone, 2004)
):
- covered by thin shell of reactive bone (Fig. 2
  Fig. 2: Gross appearance of large aneurysmal bone cyst of ulna. (Courtesy of Dr Juan Jose Segura, San José, Costa Rica)
  )
- may extend into soft tissue

Histopathology

Large spaces:
- filled with blood
- no endothelial lining
- delimited by cells:
  - with morphologic, ultrastructural, and immunohistochemical features of:
    - fibroblasts
    - myofibroblasts
    - histiocytes17,18
  - these cells also occupy septa that separate the cysts 18
- row of osteoclasts often immediately beneath surface (Figs 3 and 4
  Fig. 3: Aneurysmal bone cyst of lower end of ulna. Microscopic appearance, showing two cavities lined by osteoclast-like multinucleated giant cells. The intervening stroma is cellular but contains no neoplastic osteoid.
  Fig. 4: Microscopic appearance of aneurysmal bone cyst of lower end of fibula.
  )
Septa also contain:
- blood vessels
- foci of osteoid and bone
Deposition of peculiar degenerated calcifying fibromyxoid tissue:14
- great diagnostic significance

Diagnosis

Solid Variant Of Aneurysmal Bone Cyst19–25

Features of aneurysmal bone cysts in association with solid areas composed of:
- fibrous tissue
- new bone formation
- osteoclasts
Sometimes solid areas with this mixed appearance in absence of typical aneurysmal bone cyst features
Locations include:
- less commonly long bones:
  - tend to have a metaphysical location 26 (Fig. 7
    Fig. 7: Gross appearance of so-called ‘solid variant’ of aneurysmal bone cyst. A few hemorrhagic cystic areas are present at the periphery.
    )

Other Investigations

Radiography:
- eccentric expansion of bone (Fig. 5
  Fig. 5: Radiographic appearance of large aneurysmal bone cyst of ulna. (Courtesy of Dr Juan Jose Segura, San José, Costa Rica)
  )
- erosion and destruction of cortex (Fig. 6
  Fig. 6: Radiographic appearance of aneurysmal bone cyst of lower end of fibula.
  )
- small peripheral area of periosteal new bone formation

Differential Diagnosis

Select up to 2 differential diagnoses to compare with Aneurysmal Bone Cyst

Solitary bone cyst
Giant cell tumor
Hemangioma
Telangiectatic osteosarcoma
Giant cell reparative granuloma:
- especially for lesions in jaw
Areas grossly and microscopically indistinguishable from aneurysmal bone cyst can occur in:
- chondroblastoma
- giant cell tumor
- fibrous dysplasia
- nonossifying fibroma
- osteoblastoma
- chondrosarcoma
- vascular and cartilaginous hamartoma of chest wall in infants27
Exceptionally rare malignant transformation into osteosarcoma needs to be distinguished from:
- telangiectatic osteosarcoma
- osteosarcoma with aneurysmal cyst-like areas28

Genetics

Nonrandom cytogenetic aberrations irrespective of subtype involving chromosome segments 17p11-13 and/or 19q22

Management

Curettage:
- recurrence supervenes in ≈25% of cases due to incompleteness of surgical excision2,29
En bloc resection or curettage with bone grafting:
- better results 30
- claimed that lesions containing fibromyxoid areas and immature osteoid more likely to recur31

References

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2 Vergel De Dios AM, Bond JR, Shives TC, McLeod RA, Unni KK. Aneurysmal bone cyst. A clinicopathologic study of 238 cases. Cancer. 1992;69:2921–2931.

3 Leithner A, Windhager R, Lang S, Haas OA, Kainberger F, Kotz R. Aneurysmal bone cyst. A population based epidemiologic study and literature review. Clin Orthop. 1999;363:176–179.

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10 Buraczewski J, Dabska M. Pathogenesis of aneurysmal bone cyst. Relationship between the aneurysmal bone cyst and fibrous dysplasia of bone. Cancer. 1971;28:597–604.

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14 Tillman BP, Dahlin DC, Lipscomb PR, Stewart JR. Aneurysmal bone cyst. An analysis of 95 cases. Mayo Clin Proc. 1968;43:478–495.

15 Leithner A, Lang S, Windhager R, Leithner K, Karlic H, Kotz R, et al. Expression of insulin-like growth factor-1 (IGF-1) in aneurysmal bone cyst. Mod Pathol. 2001;14:1100–1104.

16 Sciot R, Dorfman H, Brys P, Dal Cin P, De Wever I, Fletcher CD, et al. Cytogenetic-morphologic correlations in aneurysmal bone cyst, giant cell tumor of bone and combined lesions. A report from the CHAMP study group. Mod Pathol. 2000;13:1206–1210.

17 Aho HJ, Aho AJ, Einola S. Aneurysmal bone cyst. A study of ultrastructure and malignant transformation. Virchows Arch [A]. 1982;395:169–179.

18 Alles JU, Schulz A. Immunocytochemical markers (endothelial and histiocytic) and ultrastructure of primary aneurysmal bone cysts. Hum Pathol. 1986;17:39–45.

19 D'Alonzo RT, Pitcock JA, Milford LW. Giant cell reaction of bone. Report of two cases. J Bone Joint Surg (Am). 1972;54:1267–1271.

20 Dehner LP, Risdall RJ, L'Heureux P. Giant cell-containing “fibrous” lesion of the sacrum. Am J Surg Pathol. 1978;2:55–70.

21 Oda Y, Tsuneyoshi M, Shinohara N. “Solid” variant of aneurysmal bone cyst (extragnathic giant cell reparative granuloma) in the axial skeleton and long bones. A study of its morphologic spectrum and distinction from allied giant cell lesions. Cancer. 1992;70:2642–2649.

22 Panico L, Passeretti U, De Rosa N, D'Antonio A, De Rosa G. Giant cell reparative granuloma of the distal skeletal bones. A report of five cases with immunohistochemical findings. Virchows Arch. 1994;425:315–320.

23 Sanerkin NG, Mott MG, Roylance J. An unusual intraosseous lesion with fibroblastic, osteoclastic, osteoblastic, aneurysmal and fibromyxoid elements. “Solid” variant of aneurysmal bone cyst. Cancer. 1983;51:2278–2286.

24 Wold LE, Dobyns JH, Swee RG, Dahlin DC. Giant cell reaction (giant cell reparative granuloma) of the small bones of the hands and feet. Am J Surg Pathol. 1986;10:491–496.

25 Yamaguchi T, Dorfman HD. Giant cell reparative granuloma. A comparative clinicopathologic study of lesions in gnathic and extragnathic sites. Int J Surg Pathol. 2001;9:189–200.

26 Bertoni F, Bacchini P, Capanna R, Ruggieri P, Biagini R, Ferruzzi A, et al. Solid variant of aneurysmal bone cyst. Cancer. 1993;71:729–734.

27 McCarthy EF, Dortman HD. Vascular and cartilaginous hamartoma of the ribs in infancy with secondary aneurysmal bone cyst formation. Am J Surg Pathol. 1980;4:247–253.

28 Kyriakos M, Hardy D. Malignant transformation of aneurysmal bone cyst, with an analysis of the literature. Cancer. 1991;68:1770–1780.

29 Ruiter DJ, van Rijssel ThG, van der Velde EA. Aneurysmal bone cysts. A clinicopathological study of 105 cases. Cancer. 1977;39:2231–2239.

30 Koskinen EVS, Visuri TI, Holmström T, Roukkula MA. Aneurysmal bone cyst. Evaluation of resection and of curettage in 20 cases. Clin Orthop. 1976;118:136–146.

31 de Silva MV, Raby N, Reid R. Fibromyxoid areas and immature osteoid are associated with recurrence of primary aneurysmal bone cysts. Histopathology 203, 43: 180-188.

Last updated: 16 Mar 2006