Video, 30 min

Common Bone lesions appearing cystic on X ray


Aneurysmal bone cyst metatarsal Foot swollen by an aneurysmal bone cyst of metatarsal
Aneurysmal bone cyst of 3rd metatarsal. Note how the other metatarsals have adapted to this slow growing lesion

Patients with cystic bone lesions may present with pain or swelling or the cyst may be noticed incidentally on an X Ray taken for other reasons.

Pain may indicate that the cyst is developing a stress fracture and needs urgent treatment, or it may be present for other reasons such as in the case of a ganglion cyst secondary to degenerative joint disease.

The patient commonly presents with an established fracture through a lesion that appears cystic.

Fracture through a simple bone cyst
Pathological fracture through a simple bone cyst in a 17 year old

Not all cysts require treatment. In some lesions the danger of biopsy or other surgery may outweigh any benefit.

The following lesions generally do not require operative treatment.

Tumor and tumor-like lesions for non operative treatment

Staging of Benign Bone Tumours(Enneking)
Stage 1 (latent) Stage 2 (active) Stage 3 (aggressive)

Non-ossifying fibroma

Unicameral bone cyst
Osteochondroma Osteoid osteoma
Fibrous dysplasia
Eosinophilic granuloma

Osteoid osteoma
Giant-cell tumor
Chondromyxoid fibroma
Fibrous dysplasia
Eosinophilic granuloma
Aneurysmal bone cyst
Unicameral bone cyst
Osteofibrous dysplasia
Giant cell tumor
Aneurysmal bone cyst
Biopsy of bone infarct will create to a stress riser in dead bone. A stress fracture will develop which can not heal and leads to complete fracture of the bone. Similarly a biopsy of a stress fracture will yield callus which may be mistaken by the pathologist as osteoid, leading to misguided surgery such as an amputation or block resection.

As with everything in medicine, there are exceptions. Any lesion in the above list which is painful, fast growing or large (appears as if it may immanently cause a fracture) will require surgery.

Fracture through a large non ossifying fibroma This large non ossifying fibroma  required internal fixation
This non ossifying fibroma was so large it lead to a pathological fracture and required internal fixation
A large intraosseous ganglion Intraosseous ganglion treated with bone graft
Exceptions to the rule: Intraosseous ganglion (Gode). This lesion was painful and required a vascularised graft.



Surgical options

The stage of the tumour must be taken into consideration when treatment is planned. The protocol in the table below advocated S. Gitelis can be applied to all benign lesions, including cysts.

Treatment of benign bone lesion according to surgical stage
Stage 1
Observation / Excision
Stage 2
Intralesional excision with or without adjuvant
Stage 3
Intralesional excision with or without adjuvant
Marginal or wide en bloc excision


Burring the inner wall of a cystic bone lesion Pouring liquid nitrogen to ablate surviving cells inside a bone cyst
After curettage the inner walls of the cyst are burred Cryosurgery: Liquid nitrogen is poured into the cyst to ablate any surviving tumour cells

Internal Fixation

Whether to do internal fixation or not after operating on a cyst depends on the site of the lesion. As a rule simple bone cysts do not require internal fixation and can be treated conservatively, even if they have already caused a fracture. The bone is merely treated as uncomplicated traumatic fracture, and the fact that the cyst has decompressed itself will hasten its resolution.

Any cyst in a high stress area, such as the peritrochanteric region of the femur will require open reduction and internal fixation in addition to the definitive treatment described above. Even a biopsy in this region is enough to initiate a fracture and will probably require internal fixation before the patient can be safely mobilised.

Today's Date:


(1) Enneking, W. F.:
Musculoskeletal Tumor Surgery. Vol. 1, pp. 87-89. New York, Churchill Livingstone, 1983.
(2) Enneking, W. F., and Gearen, P. F.:
Fibrous dysplasia of the femoral neck. Treatment by cortical bone-grafting. J. Bone and Joint Surg., 68-A: 1415-1422, Dec. 1986.

(3) Gitelis, S., Wilkins, R., and Conrad, E. U., III
Instructional course lectures, The
American Academy of Orthopaedic
Surgeons. Benign Bone Tumours
JBJS Vol. 77-A, No. 11, November 1995, pp. 1756-1782