Aggressive Behaviour of Thoracal Aneurysmal Bone Cyst: Case Report and Literature Review.
Happy Kurnia Brotoarianto1, Ajid Risdianto1, Muhamad Thohar Arifin2, Dody Priambada2, Erie BPS Andar2, Krisna Tsaniadi P2, Yuriz Bakhtiar2, Zainal Muttaqin2, Surya Pratama
Brilliantika2
1Neurosurgery Department, Faculty of Medicine, Diponegoro University – Neurosurgery Deparment, Subdivision Spine, Kariadi General Hospital, Semarang, Indonesia
2Neurosurgery Department, Faculty of Medicine, Diponegoro University – Neurosurgery Deparment, Kariadi General Hospital, Semarang, Indonesia
Background: Aneurysmal Bone Cysts (ABC) are pathologically benign but locally aggressive lesions. This tumor is uncommon, representing 1.4 % of primary bone tumors, 3- 30% of cases are reported in vertebral columns, and half of them are reported in pediatric age groups. Therapeutic strategies depend on their characteristics and recurrence rate. We Present the case of Aggressive behavior of ABC in Thoracal region with a literature review of this tumor.
Case Description: In this study, the case of an 11-year-old male with paraplegia and radicular pain was investigated. Spinal Imaging revealed “typical” ABC features: cyst with blood component forming lobulated fluid level shape with septations in Vertebral spinous process and bilateral lamina of Th3-4. The size of this tumor was AP 5.4 x LL 3.6 x CC 5.6 cm. This tumor spreads and compresses into paraspinal muscles, thecal sac, and the spinal cord of Th 3-5. Near-total tumor removal was performed at this time. A small part of the strongly attached tumor in non-accessible regions was coagulated. After the first surgery, radicular pain improved, and paraplegia still remains. After 6 months of follow-up, radicular pain reappears with a kyphotic clinical appearance. Re-surgery with stabilization was
performed. After follow-up, an improvement in spine stability and radicular pain were achieved.
Conclusion: Aneurysmal Bone Cysts are pathologically benign, but in some cases, have locally aggressive patterns. Despite total removal being performed, recurrence rates are still high. Treatment strategies depend on each case.
Keywords: Aneurysmal Bone Cysts (ABC), Thoracal Spine, Laminectomy
Introduction
Aneurysmal bone cysts (ABCs) are benign, highly vascular pseudotumors of unclear etiology that occur infrequently (1% of primary bone tumors). (1) However, the lesion currently regarded as a true neoplasm is neither an aneurysm nor a cyst. ABC causes around 1% of bone malignancies, with an incidence of 0.14 per 100,000 people and a frequency of 0.32 per 100,000. (2,3) ABC tends to affect younger members of the population, is more common in the second decade of life, and has a male-to-female ratio of 1:1.16 in the general population.
Most patients (76 children) were older than 10 years old, with a median age of diagnosis of 9.4 years (range: 18 months to 16 years). Overall, most cases occurred in patients older than 10 years of age, with a mean age of diagnosis of 10.2 years (range: 18 months to 17 years) found in the same article's literature review of 18 pediatric studies compiling 411 patients (212 boys and 199 girls). (2–4)
The lumbar spine accounts for 6%-22% of ABCs, while the sacrum accounts for 13%-21%.
Different types of bone malignancies, such as giant cell tumors, telangiectatic osteosarcoma, osteoblastoma, and chondroblastoma, are related to different types of ABCs. Most of the time, the back half of the spine is the target of ABCs. Between 31% and 41% of cases involve the cervical spine, 25% to 30% involve the thoracic spine, and 40% to 45% involve the lumbar spine. Selective arterial embolization (SEA), radiation, curettage, and en bloc excision followed by reconstruction are all viable alternatives. (5,6)
The symptoms of this tumor vary, usually pain because of local and neurological involvement because of this tumor. In the last stage of this tumor, ABC gains aggressive behavior by invading the non-bony structure. (7) Here, we present a case of pediatric thoracal spine ABC with aggressive tumor behavior.
Case Description
An 11-year-old male presented with progressive chronic local back pain for 1 year. At first, the pain was felt in the back, but gradually spread to the front. 2 months later, the patient began to complain of weakness in the right and left legs. Initially, he was still able to walk with assistance, but the next month, the patient was unable to walk. activities carried out with wheelchairs.
The patient was then examined at the regional hospital and then referred to our hospital.
When first admitted, the patient complained of severe back pain and paraparesis. The patient is unable to move both legs. From the physical examination, the patient is fully conscious, and vital signs are normal. Motor examination revealed spastic inferior paraparesis with motoric strength 1/1, clonus of the lower extremities (+), and autonomic bowel and bladder functions within normal limits at this time.
MRI was carried out in June 2022 with the results of a cystic lesion with a blood component in it which forms fluid-fluid levels in a lobulated shape with septations inside the corpus, pedicle, and laminae of vertebrae thoracal 3-4 with spinal canal involvement in thoracal 3-5 and invade the paraspinal muscle. MRI findings revealed a typical aneurysmal bone cyst.
(Figure 1)
The patient then underwent laminectomy of thoracic spine 3-4 with tumor excision on June 30, 2022. (Figure 2) During the operation, the tumor attached locally under the subcutaneous tissue extending to the paraspinal muscles, lamina of thoracal 3-4, and extending to the epidural. The tumor is dark red, soft, reddish, and bleeds easily. Near-total removal is carried out. postoperatively, pain improved, bowel and micturition complaints within normal limits, and motor remained 1/1. From pathological examination, there were Extradural tissue fragments consisting of striated muscle cells and mature fat cells. Fibromyxoid connective tissue stroma is hyperemic with areas of bleeding, cystic sections filled with bleeding are seen bounded by septal connective tissue, fibroblast cells, osteoclast giant cells, hemosiderin
macrophages, and foamy macrophages. There were no signs of cellular malignancy, typical presentation of an aneurysmal bone cyst. The patient is programmed for postoperative rehabilitation.
6 months after the first operation, the patient complained of pain starting to reappear in the back spreading to the front. The patient complains that it is difficult to control micturition.
because the pain could not be endured, the patient was then checked back into the hospital. At the second admission, there was motor 1, hypesthesia sensory, and radiculopathy in dermatome T3-6. The patient then underwent an MRI and found the lesion to be more progressive than pre-op, with a kyphotic thoracic curvature and 3-4 flattening of the thoracic body. A cystic lesion with a fluid component extends to the body, pedicle, lamina, and spinous process, and extends to the paravertebral column, pressing the thecal sac and medulla at 2-5 thoracic levels. size AP current admission AP 5.51 x LL 4.37 x 6.33 CC cm. (compare to before operation 5.4 x LL 3.6 x CC 5.6 cm). (Figure 3). At this admission, the patient underwent laminectomy of thoracal 2-4, tumor removal, and posterior fusion. After follow- up, the pain was decreased (VAS = 2 with oral analgetic). Symptoms of the motoric and neurogenic bladder persist. then, the patient continues to rehabilitation program every month.
Discussion
The incidence of aneurysmal bone cysts is low, representing just 1-6% of all primary bony malignancies. Annually, 0.14 cases of ABCs were recorded per 100,000 persons by a group from Austria. (8) Patients with ABCs might be of any age, from childhood on up; however, the demographic with the highest prevalence of this disorder is that of young adults. These cysts can form in any type of bone, including the long bones, the spine, and the flat bones of the body. Injuries to the vertebrae of the long bones are well-documented and rather common.
They make up seventy-five percent of all occurrences. Most often found in the lumbar region,
they also show up frequently in the cervical and thoracic regions of the spine. However, the lesion can affect any part of the vertebra, including the VB, and is most commonly found in the spine's posterior parts, notably the lamina. (9)
Additionally, the mandible, clavicle, femur, and digits are also impacted. Even though they are more common in children, adults can develop them, too, especially women in their early 20s. They are massive entities capable of leading to damage to bones and soft tissues through a process known as osteolytic destruction. Major morbidity from spinal lesions can be a consequence. (10)
Based on Enneking's classification of benign musculoskeletal neoplasms, we classify aneurysmal bone cysts as follows: Tumors at 1st stage are typically discovered inadvertently and show no symptoms. Tumors at 2nd stage are considered "active" when they cause the patient to experience physical symptoms. Constantly increasing, they may soon be felt.
Tumors at 3rd stage are considered aggressive when they cause considerable pain for the patient and/or produce a visual anomaly due to inflammation. (7) These benign tumors behave extremely closely to low-grade malignancy despite their benign status. In this patient, the tumors invade the spinal and paraspinal structures, including the spinal canal, and compress aggressively to the spinal cord. Despite the total removal of the first surgery, recurrence still occurs, and need for a second surgery.
The aneurysmal bone cyst (ABC) has been considered a reactive process since it is a locally recurring bone disease. Recently, clonal chromosome band 17p13 translocations were shown to exist in primary ABC, demonstrating a neoplastic basis in this form of ABC characterized by a spindle cell proliferation exhibiting USP6 or CDH11 rearrangements in approximately two-thirds of cases. Comparable in appearance to main ABC, but without the signature USP6 or CDH11 rearrangements of primary ABC, secondary ABC likely reflects a common endpoint of differentiation in many non-ABC bone cancers. (11) There have been reports of
specific translocations of the USP6 gene in approximately seventy percent of primary ABC lesions, but never in secondary ABC tumors. (12)
Aneurysmal bone cysts can be treated by curettage, bone grafting, excision, embolization, radiation treatment, or a combination of these methods.
However, research debates the best therapy for spine aneurysmal bone cysts. Aneurysmal bone cysts of the spine require specific care due to their anatomy. The patient's age, lesion accessibility, intraoperative blood loss, neurological compression, pathological fracture and deformity, and potential postoperative instability after complete resection must be considered.
Preoperative embolization reduces intraoperative blood loss. Adjuvant radiation may increase malignancy risk and offer little benefit over surgery alone. Excision, radiation, and selective arterial embolization have worked. Aneurysmal bone cysts might recur locally following various therapies. Wide excision has the greatest survival rate, although severe surgery may weaken the spine. Complete excision followed by spinal stabilization provides the best local control and prevents or corrects spinal deformity and instability. (13)
Spinal ABC might be treated with a medication that targets a pathway that is dysregulated in a condition with comparable pathogenesis. Denosumab is a human monoclonal antibody that blocks the effects of agonists acting on RANKL receptors by binding to the cytokine receptor activator of nuclear factor-kappa B-ligand (RANKL). This inhibits further osteoclast activation and proliferation. Denosumab has been demonstrated to be beneficial in lowering tumor bulk in cases of refractory, recurrent, or inoperable GCT in clinical studies. A significant hazard of Denosumab is osteonecrosis, which occurs when the drug prevents normal bone remodeling. (14)
Conclusion
Aneurysmal Bone Cysts are pathologically benign, but in some cases, have locally aggressive patterns. In spite of total removal being performed, recurrence rates are still high. Treatment strategies depend on each case.
Acknowledgement
All the authors would like to thank the patient for the permission to publish this case.
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Figure Legends
Figure 1. First Admission MRI, Cystic lesion with a blood component in it that forms a fluid- level fluid lobulated shape with septations inside the corpus - pedicle right and left - right left lamina - spinous process of Th.3 vertebra, right left lamina – the spinous process of Th.4 vertebra (measurement ± AP 5.4 x LL 3.6 x CC 5.6 cm) which presses on the thecal sac and spinal cord at the level of Th.3-Th.5 vertebrae, attaches and urges m. left multifidus, m.
longissimus dorsi left tends to be an aneurysmal bone cyst.
Figure 2. Pre-operation picture of first surgery
Figure 3. Second admission of MRI, lesion to be more progressive than first surgery, with a kyphotic thoracic curvature and 3-4 flattening of the thoracic body. A cystic lesion with a fluid component extends to the body, pedicle, lamina, spinous process and extends to the paravertebral column, pressing the thecal sac and medulla at 2-5 thoracic levels. size AP current admission AP 5.51 x LL 4.37 x 6.33 CC cm. (compare to before first operation 5.4 x LL 3.6 x CC 5.6 cm).
