Solitary Osteochondroma of the Skull Base: A Case Report and Literature Review

Intracranial osteochondroma arising from the posterior clinoid process: a rare case report with diagnostic challenges and comprehensive literature review

Introduction and importance

Intracranial osteochondroma is rare, presenting diagnostic challenges due to overlapping imaging findings with other pathologies. This case report highlights the significance of considering osteochondroma in calcified tumour differentials near bone.

Case presentation

A 34-year-old man with vision deterioration and headaches had an MRI revealing a suprasellar lesion. Intraoperatively, a bony hard tumour was partially resected. Subsequent computed tomography (CT) confirmed a calcified mass contiguous with the posterior clinoid.

Clinical discussion

Reviewing 28 cases, skull base osteochondromas were common, with differential diagnoses including craniopharyngioma and meningioma. Surgical decision-making involved balancing complete resection for convexity and falx cases versus partial resection for skull base tumours due to proximity to critical structures.

Conclusion

Intracranial osteochondroma poses diagnostic challenges, especially near bone. Tailored surgical approaches are vital, with complete resection yielding good outcomes for convexity and falx cases. Close follow-up is crucial for monitoring recurrences and complications.

Benign bony tumors of the paranasal sinuses, orbit, and skull base

Benign bony tumors of the skull base and paranasal sinuses are uncommon entities, with an overall higher incidence in males. Benign bony tumors may lead to local expansion with resultant mass effect of potentially critical structures. Some benign bony tumors may undergo malignant transformation. This article reviews the presentation and management of benign bone tumors of the skull base and paranasal sinuses with special consideration to involvement of the adjacent orbit, intracranial and critical neurovascular structures. This review covers tumor incidence, location, gross and histologic appearance as well as radiographic findings, treatment, and recurrence rates. Tumors discussed in this article include osteochondromas, osteomas, osteoid osteomas, aneurysmal bone cysts, fibrous dysplasia, giant cell tumors, cemento-ossifying fibroma, ameloblastic fibro-odontoma, ecchordosis physaliphora, chondromyxoid fibroma, primary chronic osteomyelitis, primary chronic osteomyelitis, osteochondromyxoma, and dense bone islands.

Clinical and Radiologic Characteristics, Surgical Outcomes, and Its Possible Origins of Chondroma of the Dural Convexity

Chondroma of the dural convexity (CDC) is a benign and extremely rare type of intracranial chondroma. In this study, we reported five CDCs in a single center and reviewed the available literature to determine the clinical characteristics and surgical outcomes and possible origins of the disease. The clinical data of five patients (4 females) who confirmed to be CDC between 2000 and 2019 in our single center was collected together with 22 cases from literatures. The clinical characteristics and surgical outcomes were reviewed and analyzed. Among all the available CDC cases, the mean age was 31 ± 13.7 years; the mean tumor volume was 42.3 ± 40.9 cm³, showing a female predominance (63% vs. 37%). The tumors showed calcification in 88.2% cases (15/17) on CT scans and hypointense on T1WI (15/19, 78.9%), mixed intense on T2WI (10/18, 55.6%), and inhomogeneous enhancement without dural tail sign after administration of gadolinium (20/21, 95.2%). Almost all the tumors were misdiagnosed as meningiomas preoperatively. In addition, almost all image available CDC lesions (24/25, 96%) located across the cranial sutures indicating that the tumor originated from ectopic chondrocytes from adjacent skull sutures. No tumors recurred after total resection in follow-up. CDCs are characterized with female predominance and may originate from ectopic chondrocytes from adjacent skull sutures. The lesion with inhomogeneous contrast enhancement without dural tail sign and avascular in cerebral angiography are key points to be differentiated from meningioma. The most effective treatment is total resection.

Foramen magnum osteochondroma causing myelopathy in a patient with hereditary multiple exostoses

Background:

Osteochondromas are commonly occurring benign bone tumors which may be either a solitary lesion or occur due to association with hereditary multiple exostoses (HMEs). There have been several reported cases of spinal osteochondromas, but intracranial lesions are rare.

Case Description:

A 51-year-old male with a history of multiple osteochondromas presented with myelopathy. He had an exostosis arising from the foramen magnum causing compression of the cervical spinal cord that was successfully removed. Genetic testing revealed that he had HMEs.

Conclusion:

Osteochondromas of the skull are extremely rare. However, parts of the foramen magnum ossify in cartilage and can give rise to an osteochondroma. Here, we present a patient with HMEs who developed cervical myelopathy due to an osteochondroma arising from the foramen magnum. Due to the cartilaginous ossification of the foramen magnum, clinicians should be aware that osteochondromas can occur in this location and potentially give rise to cervical myelopathy.

A multidisciplinary approach for the treatment of young patients with suprasellar osteochondroma

BACKGROUND

Osteochondroma is the most common benign bone tumor; intracranial osteochondroma is a very rare finding in the neurosurgical literature and most of them arise from the skull base.

CASE REPORT

We report a case of suprasellar ostheocondroma in a 16-year-old female, with its CT and MRI appearances, which caused visual deficits, resolved after surgery.

DISCUSSION

To our knowledge, this is the fifth case of osteochondroma affecting the suprasellar region that has been reported, with all the characteristic features of this tumor: optic chiasmal syndrome, intralesional calcifications, cartilage cap, and contrast enhancement.

CONCLUSION

Multidiscplinary teams, including a neuro-ophthalmologist, endocrinologist, neuroradiologist, neurosurgeon, and neuropathologist are needed for correct treatment of the disease and appropriate follow-up.

Joint Capsule-Like Intracranial Osteochondroma Mimicking Cystic Meningioma

This report provides the first representative images of an intracranial osteochondroma with a cystic component mimicking cystic meningioma. A 40-year-old male presented at our outpatient clinic with decreased sensation in his right upper extremity. Preoperative computed tomography showed a tumor with a cystic meningioma-like appearance and prominent calcifications. On magnetic resonance imaging, calcification of the lesion was suggested by the T2-weighted image; weak enhancement was seen on the T1-weighted image. Following surgical removal of the tumor, the pathologic examination showed findings consistent with osteochondroma. Cystic meningioma is a rare tumor with a cystic component. Intracranial osteochondroma is also a rare, benign tumor that can mimic meningioma when presenting in the dural convexity. Our report describes the joint capsule-like appearance of a convex cystic osteochondroma including a calcified cap, bonelike structure, and fluid-containing intracapsular space. The tumor was evaluated by imaging and pathologic studies.

Multiple osteochondromas of the antlers and cranium in a free-ranging white-tailed deer (Odocoileus virginianus)

This paper reports a case of multiple osteochondromas affecting the antlers and the left zygomatic bone of a free-ranging adult white-tailed buck (Odocoileus virginianus) from Georgia, USA. Along with a few postcranial bones, the antlered cranium of the individual was found in a severely weathered condition and devoid of any soft tissue. The antlers exhibited five pedunculated exostoses that were composed of cancellous bone and, in their peripheral portions, also mineralized cartilage. The largest of the exostoses, located on the right antler, had a maximum circumference of 55 cm. The exostosis arising from the zygomatic bone was broad-based and much smaller than the exophytic outgrowths on the antlers. Diagnosis of the exostoses as osteochondromas was based on their overall morphology, the normal bone structure in their stalk regions, and the continuity of their spongiosa and cortex with the respective components of the parent bones. Antleromas, i.e., pathological outgrowths developing on antlers as a result of insufficient androgen production, were excluded in the differential diagnosis, based on (1) the apparent maturity and, except for the tumors, normal shape of the antlers and (2) the fact that exostosis formation had also affected the zygomatic bone. Previously only a single case of solitary osteochondroma of an antler has been described in the scientific literature. The case presented here is the first report of multiple osteochondromas in a deer. As antlers are regularly collected as trophies, and huge numbers of them are critically inspected each year, the fact that thus far only two cases of antler osteochondromas have been reported suggests that these tumors are very rare.