Case report 566: Osteoblastoma of sacrum with secondary aneurysmal bone cyst

Aneurysmal bone cyst and osteoblastoma: an extremely rare combination in the pediatric spine

STUDY DESIGN

Case report.

OBJECTIVE

To report the clinical and imaging findings of a patient with the extremely rare association of aneurysmal bone cyst and osteoblastoma in the cervical spine. To our knowledge, only three cases have been reported in the published literature in children under 16 years of age with this condition in the cervical spine.

METHODS

The patient's history, physical examination, imaging findings, and management with a complete 4-year medical history, surgical intervention and radiological follow-up are reported.

RESULTS

A 4-year 11-month-old boy was diagnosed with aneurysmal bone cyst in association of osteoblastoma and was treated with CT-guided intralesional injection calcitonin and methylprednisolone. During the course of intralesional therapy, a pathological fracture of C2 was produced. Subsequently, a widened intralesional excision and instrumented fusion from occiput to cervical spine (C0-C4) was performed.

CONCLUSION

The association of aneurysmal bone cyst and osteoblastoma in spine is extremely rare. Although both are benign lesions, in the cervical location, complete removal of the tumors is challenging. Wide resection with reconstruction of the segments for stability associated with adjuvant treatment with calcitonin and corticosteroids provides a good option.

C4 cervical spine osteoblastoma associated with secondary aneurysmal bone cyst in an adolescent patient: 2-year follow-up

Introduction

Osteoblastoma and aneurysmal bone cyst (ABC) are rare bone tumors with individual prevalence of <1%. Their combined occurrence is a rare subclass of tumors in the spinal column with only a few cases reported in literature.

Case presentation

The present case is a rare combination of aggressive osteoblastoma with secondary aneurysmal bone cyst masquerading as neck pain, arising from cervical C4 vertebra in a 19-year-old male. The patient presented with complaints of neck pain for 7 months, gradual in onset, dull, aching, and progressively increasing in severity. Neurological examination was normal. Radiology showed an expansile lytic mass arising from the posterior elements of C4 vertebra involving the left lateral mass. Piecemeal total removal was done and a posterior fusion from C3 to C5 was performed for stability. Histopathology confirmed the osteoblastoma with a secondary aneurysmal bone cyst. Postoperatively the patient recovered well, and no recurrence was seen on a 2-year follow-up.

Discussion

Simultaneous presence of an osteoblastoma with a secondary ABC arising from various bones, such as cranial fossa, ethmoid sinus, skull, and mandibular condyle, has rarely been reported. It is often diagnosed late due to nonspecific symptoms; but it has a good prognosis if early and complete resection is performed. Thorough surgical excision is always a challenge in spine cases due to surrounding important structures and meticulousness is required to prevent any recurrences. Hence, we recommend a surgical team comprising both spine and musculoskeletal oncologic surgeons to achieve best results.

Osteoblastomas of the spine: a comprehensive review

Osteoblastomas are primary bone tumors with an affinity for the spine. They typically involve the posterior elements, although extension through the pedicles into the vertebral body is not uncommon. Histologically, they are usually indistinguishable from osteoid osteomas. However, there are different variants of osteoblastomas, with the more aggressive type causing more pronounced bone destruction, soft-tissue infiltration, and epidural extension. A bone scan is the most sensitive radiographic examination used to evaluate osteoblastomas. These osseous neoplasms usually present in the 2nd decade of life with dull aching pain, which is difficult to localize. At times, they can present with a painful scoliosis, which usually resolves if the osteoblastoma is resected in a timely fashion. Neurological manifestations such as radiculopathy or myelopathy do occur as well, most commonly when there is mass effect on nerve roots or the spinal cord itself. The mainstay of treatment involves surgical intervention. Curettage has been a surgical option, although marginal excision or wide en bloc resection are preferred options. Adjuvant radiotherapy and chemotherapy are generally not undertaken, although some have advocated their use after less aggressive surgical maneuvers or with residual tumor. In this manuscript, the authors have aimed to systematically review the literature and to put forth an extensive, comprehensive overview of this rare osseous tumor.

Benign osteoblastoma of the odontoid process of the axis with secondary aneurysmal bone cyst component: a case report

The authors report their experience on one patient with osteoblatoma of the odontoid process of the axis with secondary aneurysmal bone cyst. According to their knowledge, this is the first case, reported in the literature, of this kind of lesion in that particular anatomical region. Because of the rarity of this lesion, it was difficult to have a certain preoperative diagnosis. Therefore, the patient underwent a biopsy via a transoral route. The biopsy was performed over the noncalcified component of the lesion. The intraoperative histological examination showed the benign nature of the lesion. Thereafter, the lesion was totally removed, succeeding in preserving the remaining part of the odontoid process and the anterior arch of C1. In the follow-up, there was no evidence of cranio-vertebral instability. The histological examination revealed an osteoblastoma of the odontoid process of the axis with a secondary aneurysmal bone cyst. To the best of our knowledge, this is the first case reported in the literature.

Magnetic resonance imaging of benign bone lesions: cysts and tumors

A benign bone lesion may have a typical appearance on plain radiographs. This is the case with benign cortical defects and osteochondroma. With most other lesions, cross-sectional imaging is needed to complete the study of the tumor. The nidus of osteoid osteoma is well demonstrated on computed tomography, but magnetic resonance imaging also will show the nidus in most cases. Magnetic resonance imaging is considered the modality of choice for evaluation of other benign musculoskeletal lesions because it is highly sensitive to changes in the signal intensity of bone marrow and adjacent soft tissues. It provides useful information for diagnosis of the lesion as in primary or secondary aneurysmal bone cyst, chondroblastoma, osteoblastoma, fibrous dysplasia, and osteofibrous dysplasia, and it helps differentiate these lesions from osteomyelitis, Langerhans' cell histiocytosis, and stress fracture. Bone scanning is most useful for depicting multiple silent lesions as may be seen in multiple osteochondromatosis, nonossifying fibromas, and polyostotic fibrous dysplasia.

Osteoid osteoma and osteoblastoma of the sacrum

This retrospective study examined 10 patients with osteoid osteoma and 11 patients with osteoblastoma localized in the sacrococcyx. In the sacrum, the diagnosis was delayed compared to other sites. Curettage through a posterior approach is the treatment of choice. Radiotherapy as well as embolization of feeding arteries may be used for the most aggressive lesions. Prognosis is generally good with a low incidence of local recurrence (<10%).

A rare bone tumor in an unusual location: osteoblastoma of the vertebral body

Most osteoblastomas involve the posterior elements alone, or both the posterior elements and the vertebral bodies. Osteoblastomas confined in the body of the vertebrae are very rare. Spinal osteoblastomas are associated with localized pain in about 80% of cases and neurological deficits in 25% to 50% of cases. Nearly half of lumbar and thoracic osteoblastomas demonstrate coexistent scoliosis with the convex side away from the involved side of the vertebrae.