Osteoma in the upper cervical spine: A case report and comprehensive literature review

Introduction and importance Osteoma is a benign, and usually asymptomatic bone tumor normally found in the skull and facial bones, although it can occasionally occur in the long bones and spine. Case presentation In this article, we present a 49-year-old male patient who experienced progressive neck pain accompanied by left-sided radicular pain symptoms. Clinical investigation using various imaging techniques confirmed a bone-forming lesion located within the C1 vertebrae region. Treatment involved performing hemilaminectomy of C1 along with resection for complete removal of this extradural bone lesion, ultimately achieving symptom relief. Histopathological examination of the resected specimen leads to the diagnosis of osteoma. Along with reporting this case, we conducted a comprehensive literature review of the previously reported spinal osteoma cases. Clinical discussion Histopathological examination confirmed the diagnosis of osteoma. A comprehensive literature review was conducted, revealing 16 previously reported cases of spinal osteoma. Among these, only one case involved the C1 vertebra and presented similar neurological symptoms. The review underscores the rarity of spinal osteomas and the importance of surgical intervention for symptom relief. Conclusion Spinal osteomas are rare but should be considered in the differential diagnosis of patients presenting with neck pain and radicular symptoms. Surgical removal of the lesion is often necessary for symptom relief, as highlighted by our case and supported by the literature review. This case adds to the limited body of evidence on spinal osteomas and emphasizes the importance of a multidisciplinary approach for optimal patient outcomes.

Introduction and importance: Osteoma is a benign, and usually asymptomatic bone tumor normally found in the skull and facial bones, although it can occasionally occur in the long bones and spine.Case presentation: In this article, we present a 49-year-old male patient who experienced progressive neck pain accompanied by left-sided radicular pain symptoms.Clinical investigation using various imaging techniques confirmed a bone-forming lesion located within the C1 vertebrae region.Treatment involved performing hemilaminectomy of C1 along with resection for complete removal of this extradural bone lesion, ultimately achieving symptom relief.Histopathological examination of the resected specimen leads to the diagnosis of osteoma.Along with reporting this case, we conducted a comprehensive literature review of the previously reported spinal osteoma cases.Clinical discussion: Histopathological examination confirmed the diagnosis of osteoma.A comprehensive literature review was conducted, revealing 16 previously reported cases of spinal osteoma.Among these, only one case involved the C1 vertebra and presented similar neurological symptoms.The review underscores the rarity of spinal osteomas and the importance of surgical intervention for symptom relief.Conclusion: Spinal osteomas are rare but should be considered in the differential diagnosis of patients presenting with neck pain and radicular symptoms.Surgical removal of the lesion is often necessary for symptom relief, as highlighted by our case and supported by the literature review.This case adds to the limited body of evidence on spinal osteomas and emphasizes the importance of a multidisciplinary approach for optimal patient outcomes.

Background
Osteomas are benign osteogenic, slow-growing tumors located mainly near the paranasal sinuses and orbital region, and are typically localized lesions without systemic dissemination.[1].Osteomas affecting the upper cervical spine are exceedingly uncommon [2,3]; sensory deficits and clinical presentation due to canal stenosis are its main complications that necessitate prompt clinical attention.While osteomas arising from the nasal sinuses or orbital cavity can lead to sinusitis or exophthalmia, cranial osteomas generally remain clinically inconspicuous [4,5].Treatment approaches depend on the lesion's location, size, and patient symptoms, with surgical intervention typically reserved for cases exhibiting symptoms or functional impairment [6].Surgical intervention serves as the primary management approach for upper cervical spine osteoma.However, the anatomical complexity of this region presents distinct challenges during surgical procedures [7].
Here, we present a case study involving a patient who experienced neck pain radiating to his left hand due to an osteoma in their C1 vertebra.Both complaints were successfully resolved without any complications through hemilaminectomy and resection of an extradural bone lesion.Moreover, we conducted a comprehensive literature review of the 14 reported cases of spinal osteomas in the literature, with only one located in the C1 vertebra.This highlights the rarity of our case and underscores the need for reporting and analyzing such unique occurrences to enhance our understanding of osteomas in the upper cervical spine.
This work has been reported in line with the SCARE criteria to ensure standardized and high-quality reporting [8].

Case presentation
A 49-year-old man was referred to the neurosurgery department in Chamran Hospital, Fars, Shiraz, Iran, complaining of progressive neck pain and left-sided radicular pain persisting for a period of 6 months.Additionally, the patient experienced hypoesthesia and paresthesia in the left hand approximately two weeks before seeking medical attention.The patient denied any history of trauma prior to the onset of symptoms.Notably, the pain did not extend to the lower back or hips, and no numbness in the lower extremities was reported.Past medical and drug history was unremarkable, as was the patient's social history.The patient also reported no congenital abnormalities in the upper cervical spine.The patient exhibited normal cranial nerve function, muscle power, and gait.
Computed tomography (CT) scan displayed a well-delineated ovoid bony mass on the left side of C1 pedicle that mildly extended into the spinal canal, with cortical density on bone window without evidence of significant cord compression (Fig. 1).Magnetic resonance imaging (MRI) of the cervical spine indicated a mild deformity in the C1 left pedicle, resulting in thecal sac compression and mild canal stenosis, however, no atlanto-axial dislocation was observed.The evaluation determined that the sagittal diameter of the spinal canal at the C1 level was within the acceptable range of measurements.Based on the assessment, the impression was C1 benign bone forming tumor, leading to the patient undergoing an operation.During the procedure, a hemilaminectomy of C1 and total resection of the extradural bone lesion were performed.
Histopathological examination of the resected specimens revealed fragments of mature cortical type bone architecture with areas of endochondral ossification, showing no cellular atypia or necrosis.The diagnosis of the specimens and extradural bone lesion was suggestive of osteoma (Fig. 2).The patient's post-operative course has been uneventful, with relief from symptoms and disappearance of radiating pain.Also, a postoperative CT scan confirmed the complete removal of the osteoma.

Discussion and conclusion
In this article, a case of osteoma in the C1 region is presented with upper cervical canal stenosis.Hemilaminectomy of C1 and complete resection of the extradural bone lesion was performed.Accurate diagnosis of osteomas in this anatomical region poses significant challenges as they have radiologic and clinical overlap with other medical  conditions, making them difficult to detect [6].Kanaya et al. reported a C1 osteoma while conventional CT and MRI scans in the neutral position did not reveal an obvious cause, a rotational myelo-CT scan showed a bony lesion leading to the diagnosis [2].However, challenges in utilizing this technique among patients experiencing intense radiating pain during prolonged positioning limit its applicability in such cases [2].This highlights the diagnostic challenges associated with osteomas of the cervical region.More to the point, other clinical entities like a unilateral atlantoaxial (C1-C2) pseudoarticulation and osteochondroma can mimic cervical osteoma making the radiologic diagnosis difficult with conventional modalities like CT scan and MRI [7,9].Of note, obtaining adequate tissue sampling and complete resection is critical for confirming the diagnosis when clinical suspicion for an osteoma exists., A.
We conducted a literature review of all cases of spinal osteoma, listed in Table 1 [2,3,6,7,[10][11][12][13][14][15].These cases demonstrated similarities in terms of neurological symptoms and the necessity for surgery, resulting in symptom improvement postoperatively.However, there were variations in tumor location; among these cases, in eight of them the tumor was located in the cervical spine [2,3,[10][11][12][13], and in only two of the cases including the present case, the tumor was located in C1 vertebra [2].The location of the rest of the osteomas presented varies between the suboccipital bone [7], thoracic [14][15][16], lumbar [6,12], and sacrum [12].The rarity of osteomas in the C1 region was evident from the limited number of reported cases in the literature.Furthermore, a study by Peyser et al. reported five patients who underwent subtotal resection of the lesion, indicating that relief of symptoms cannot be guaranteed, and indicated that total resection should be considered as the preferred approach [12], although Wang et al. in 2006 presented a case with C2 lamina osteoma that underwent laminectomy of C2 and C3, partial removal of the tumor led to significant improvement in symptoms [3].This variety of cases emphasizes the importance of personalized treatment strategies; partial tumor removal [3,12], focused decompression [7], and total tumor removal [2,3,6,7,[10][11][12][13]16] were employed in some cases, suggesting the effectiveness of diverse surgical methods in managing cervical osteomas.
In conclusion, our case report and comprehensive literature review enhance the understanding of osteomas in the upper cervical spine.By presenting a rare case of osteoma in the atlas and analyzing existing studies, we contribute to the body of knowledge surrounding the accurate diagnosis and surgical management of these lesions.

C1
First cervical vertebra C2 Second cervical vertebra C3 third cervical vertebra CT Computed Tomography MRI Magnetic Resonance Imaging
XXX University of Medical Sciences.The purpose of this report was completely explained to the patient and written inform consent was obtained from the patient.

Fig. 1 .
Fig. 1. preoperative cervical computed tomography (CT) scan revealed the presence of a bony lesion on the left pedicle of the C1 vertebra that extends into the spinal canal.

Fig. 2 .
Fig. 2. analysis revealed that the lesion consisted of uniformly dense and compact cortical-like mature bone, without any cellular atypia consistent with the diagnosis of osteoma.

Table 1
Reported cases of spinal osteoma.