Bone cysts

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Bone cyst in the ulna of a dog[1]

Bone cysts are an idiopathic fluid-filled benign dysgenesis that may occur as monostotic (solitary) or polyostotic (numerous)[2] disease.

Bone cysts may occur in any long bones, particularly the ulnar, radius and femur and is commonly reported in young dogs from 6 weeks of age[3].

In early stages, dogs are asymptomatically affected, but as the condition advances, pain, swelling, lameness[4][5] and pathological fracture[6] have been reported.

Polyostotic bone cysts are commonly reported in Doberman dogs where it is thought to be heritable[7], but has also been reported in Mastiff and Golden retriever breeds[8].

Diagnosis is usually based on presenting clinical signs and radiographic imaging, which often shows expansile, radiolucent areas in the metaphysis of long bones[9].

A differential diagnosis would include other neoplastic bone conditions such as osteoma, osteochondroma, intraosseus lipoma[10] and osteosarcoma[11].

Treatment usually requires surgical excision or curettage if clinical signs of lameness are present, although spontaneous healing may occur.

Aneurysmal bone cysts have also been reported in dogs. These are benign, blood-filled cyst with adjacent solid areas. A similarity to Gorham-Stout syndrome in humans, characterized by a negative calcium balance is implicated in this rare condition[12].

Aneurysmal bone cyst, without osteolysis and/or damages to the surrounding tissues, usually respond to curettage and treatment with bone cement[13].

Rare cases of malignant transformations of aneurysmal bone cysts have been reported, with chondrosarcomas appearing at the site of the benign cyst three years later[14].

References

  1. Uni of Pennsylvania
  2. Carrig CB et al (1975) Polyostotic cystic bone lesions in a dog. J Small Anim Pract 16:495
  3. Jacobson SA (1971) The Comparative Pathology of Tumors of Bone. p 253. Springfield, IL, Charles C Thomas
  4. Biery DN et al (1976) Bone cysts in the dog. J Am Vet Radiol Soc '17:202
  5. Brady MA et al (1999) What is your diagnosis? Bone cyst causing acute lameness in a dog. J Am Vet Med Assoc 213(7):957-958
  6. Choate CJ & Arnold GA (2011) Elbow arthrodesis following a pathological fracture in a dog with bilateral humeral bone cysts. Vet Comp Orthop Traumatol 24(5):398-401
  7. Carrig CB & Seawright AA (1969) A familial canine polyostotic fibrous dysplasia with subperiosteal cortical defects. J Small Animal Pract 10:397
  8. Gourley J & Eden CW (1954) Bone cyst in a dog. Vet Rec 66:63
  9. Stickle R et al (1999) Radiographic diagnosis - benign bone cyst. Vet Radiol Ultrasound 40(4):365-366
  10. Nakladal Bet al (2012) Intraosseous lipoma in the ulna and radius of a two-year-old Leonberger. Vet Comp Orthop Traumatol 25(2):144-148
  11. Vanel M et al (2011) Imaging of primary bone tumors in veterinary medicine: Which differences? Eur J Radiol Dec 23
  12. Wimsatt J et al (2011) Multicystic bone disease (Gorham-Stout syndrome) in a spider monkey (Ateles geoffroyi ). J Med Primatol 40(2):61-70
  13. Sarierler M et al (2004) Bone cement treatment for aneurysmal bone cyst in a dog. J Vet Med Sci 66(9):1137-1142
  14. Barnhart MD (2002) Malignant transformation of an aneurysmal bone cyst in a dog. Vet Surg 31(6):519-524