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1. SIMPLE BONE CYST
AND
ANEURYSMAL BONE CYST
Presenter- Dr. Nithin M (2nd year PG)
Moderators–
Dr. V V Narayan rao (M.S Ortho)
Professor and Unit Chief
Dr. Alekhya K (M.S Ortho)
Assistant Professor

2. Simple Bone Cyst
 Unicameral Bone Cyst.
 Benign lesionof unknown aetiology.
 Unilocular.

3. Age
 Childhood and earlyadolescence (1st 2 decades)
 Before theepiphyseal fusionoccur.
 In adults, some lesions occurafterskeletal
maturation in such bonesas the Calcaneus, Talus

4. Location
 Most frequently found in the metaphysis.
Sites :
 Proximal humerus
 Proximal femur
 Other long bones
 Calcaneus, Talus.

5. Clinical Features
 Asymptomaticand found incidentally.
 Onlya few produce minordiscomfort. May be
pain, swelling and stiffnessof adjacent joint.
 More than half presentdue toa pathological
fracture.

6. Pathology
 Cystcontainsclear liquid unless there has been
contamination by bleeding following a fracture .
 Cyst is lined bya thin layerof connective tissue.

7. Investigations
 Plain X-ray film
 CT Scan
 MRI
 Bone Scan.

8. Plain X-ray
 An area of translucencycentrally in the metadiaphysis is
characteristic.
 The overlying cortex is often thinned and slightly expansed
with no periosteal reaction unlessa fracture has occurred.
 Scleroticreaction is usuallypresentaround the
margin.
 A serpiginous margin (by prominent ridges of bone) may
cause thecyst toappear multilocular.

12. Fallen fragmentsign
If there is fracture through this lesion, a dependent bony
fragment may be seen, and this is knownas the fallen fragment
sign.

16. Bone scan
Noabnormalitydevelops in the blood-pool phase.

17. Treatment
1)If small and lowrisk of fracture
 Somecases resolvespontaneouslywith age.
 Intralesional Steroid
 An injection of Methylprednisolone Acetate into the
lesion in several intervals fora timespan of 6-12
months.
 Complications are infection, fractureor recurrence.

18. 2)If risk of fractureor large lesion
 Curettage
 Bonegrafting
 It is proceeded aftercurettage. Theemptycavity is
transplanted with donor bone tissue, bone chips or
artificial material.

19. Differential diagnosis
1. Fibrousdysplasia
2. Aneurysmal bonecyst
3. Giantcell tumor
4. Eosinophilic granuloma
5. Nonossifying fibroma
6. Chondroma.

20. ANEURYSMALBONECYST

21. Definition
 Benign, expansile lesion with blood filled cavities
separated by septa of trabecular bone or fibrous
tissue containing osteoclast giant cells.
 The term aneurysmal is derived from its
macroscopic appearance – sponge like tumour
containing numerous giant cells.

22. Etiology
 Thetrue etiology of ABCsis unknown.
 It’s believe that ABCs are the result of a
vascular malformation within the bone.

23. Theories
 Three commonly proposed theories are as
follows:
i. May arise without evidence of another
lesion are classified as Primary ABCs (65-
99%).
ii. Caused by a reaction Secondary to another
bony lesion (1-35%) like GCT, osteoblastoma,
chondroblastoma, and osteogenic sarcoma.
iii. May arise in an area of previous Trauma.

24. Incidence and Demographics
 ABCis found at anyage
 Around 75%:before20 yearsand rareafter30 years
 Female: Male = 2 : 1

25.  Site - can be found in any bone in the body. The most
common location is the metaphysisof long bones of
lower extremity.
 About 12-30% of the ABCs involve the spine that
represents only 1.4 % of primary vertebral column
tumors.
 Spine:
 Most common in the thoracolumbar region
 The cervical spine is involved in 30-41 %.

26. Presentation
 Other findings may include the following:
 Deformity
 Decreased movement, weakness, or stiffness
 Occasionally, bruit over the affected area
 Warmth over the affected area
 Patients usually present with pain, a mass,a pathologic fracture,
or combination of these symptoms in the affected area.
 Neurologic symptoms may develop when involving the nerve,
typically in the spine.

27. Histology
 Aneurysmal bone cyst consists of blood-filled spaces of
variable size that are separated by connective tissue
containing trabeculae of bone or osteoid tissue and
osteoclastgiantcells.
 Theyare not lined by endothelium.

28. Development of ABC
It follows3 stages-
Stage Description
I Initial phase Osteolysis without peculiar findings.
II Growth phase •Rapid increase in size of osseous erosion.
•Enlargement of involved bone.
•Formation of shell around central part of lesion.
III Stabilization phase Fully developed radiological pattern.

29. Imaging Modalities
1. X- ray
2. CTscan
3. MRI
4. Nuclear Imaging
5. Angiography

30. X-Ray Appearance
 ABC is normally placed in the metaphysis and appears as a
osteolytic lesion. The periosteum is elevated and the cortex is
eroded to a thin margin.
 The expansile nature of the lesion is often reflected by a
"blown-out" or "soapbubble"appearance.
 The lesion rarely penetrates the articular surface or growth
plate.

32. X-ray cervical spine showing destruction of the C3 vertebral body and its posterior
elements.

33. Computed Tomography
 Cross-sectional CT is the most useful imaging examination, because it
can demonstrate the intraosseous and extraosseous extents of the
lesion.
 CT can be used to determine the nature of the matrix of the tumor,
especially when tumors are in complex locations, such as the facial
skeleton, spine, thoracic cage, and pelvis.
 Spinal CT can demonstrate stenosis of the spinal canal due to
involvement of the posteriorelements.

34. CTof aneurysmal bone cyst.

35. Magnetic Resonance Imaging
 MRI images of aggressive lesions show tumor enhancement with
gadolinium enhancement, especially when they are associated
with other tumors.
 Spinal cord compression and signal-intensity alteration in the
cord can be evaluated when neurologic symptoms are present.
 Fluid-fluid levelsmay be seen in the cysts.

36. Magnetic Resonance Imaging of the cervical spine demonstrating grossly
compressed and collapsed C3 vertebral body with ballooning of the posterior
arch due to a mass extending from C2 to C5

37. Fluid - fluid level (nonspecific)
FFLresults from separation of 2 fluids of different densities within a cavernous space
Mnemonic
•
•
•
•
•
•
•
•
G:giant celltumour
O: osteoblastoma
A: aneurysmal bone cyst
T:telangiectatic osteosarcoma
S: sarcomas
C: chondroblastoma
S: solitary bone cyst
F: fibroxanthoma

38. Increased radioisotope uptake peripherally with a photopenic center.
"doughnut sign"
Nuclear Imaging

39. Angiography
 On angiograms, ABCsare hypervascular lesions.
 This feature is contrary to that of other malignant lesions, such
as osteosarcoma and chondrosarcoma, which have gross hyper
vascularity.
 Hyper vascular regions in aneurysmal bone cysts may affect the
prognosis, because the number and size of the lesions are
positively correlated with the likelihood of lesional recurrence
after treatment.

40. Angiography examination of ABCof a 13-year-old male showed an expansile
lesion involving the left inferior pubic ramus and ischium.

41. Differential Diagnosis
 Simplebonecyst
 central location, before epiphyseal fusion
 absenceof expansion
 lack of cortical discontinuity
 Giantcelltumorof bone
 occurs in patients over age 20 -40 year
 expansile, eccentric, wide zone of transition
 begin in epiphysis with extension into
metaphysis
 involves joints or adjacent bone or soft tissue
 Osteoblastoma
 may havea“soap bubble” expansile appearance
 no fluid level on CT/MR
 Fibrousdysplasia
 ground-glass opacities: 56%
 homogeneously sclerotic: 23%
 well circumscribed lesions
 no periosteal reaction
 Chondroblastoma
 arising eccentrically in the epiphysis of long bone
 internal calcifications can be seen in 40-60% cases
 Sizeranges from 1-10 cm, most are 3-4 cm at diagnosis
 Chondromyxoidfibroma
 - knee joint (2/3)
 well defined radiolucent, eccentric in metaphysis
 marginal sclerosis

42. Treatment
 Preoperative embolization
 Curettage & bonegrafting
 Complete resection with bone graft
 Radiotherapy
 Steroids & Calcitonin
The treatment of choice for aneurysmal bone cysts is
gross total resection, which is curative when feasible.

43. Embolization
 Embolization can be used as first-line and the sole therapy for
ABCs.
 Several successful cures after embolization of ABCs have been
reported.
 In addition, embolization is used preoperatively to decrease
intraoperative blood loss and morbidity.

44. Surgery
• Surgically, complete excision of the tumor is the
goal but may be difficult.
• Incomplete tumor excision may be associated with
significant rates of tumor recurrence.
• Spinal reconstructions via anterior or posterior
approaches are recommended when bone removal
is extensive.

45. Radiotherapy
 Radiotherapy can be considered in patients with
residual or recurrent tumor.
 ABCs are sensitive to radiation, but the recurrence
rate remains significant despite adjuvant
radiotherapy.
 Usually 26 to 30 Gy are used.

46. Prognosis
 Recurrence rate 20-30%
 Partial resection or curettage has been associated
with recurrence rates as high as 71%.
 Despite high recurrence rates, cases of spontaneous
regression of ABCs have also been reported

47. Simple bone
cyst
Aneurysmal bonecyst
Site Metadiaphysis Typically in the metaphysis
Bonescan Noabnormality
develops
Rich increase invesselsand early
venous filling
CT & MRI
(f luid-
f luid
levels)
Absent Are thecharacteristic
Association Absent May be with non-ossifying
fibroma, fibrousdysplasia and
chondromyxoid fibroma
Cyst Clearliquid and
always
unilocular
Contains blood withgiantcells
and multilocular.

49. THANK YOU