Natural history of chondroid skull base lesions--case report and review

Central Skull Base Anatomy and Pathology: A Review

The central skull base is an anatomically complex region of the head and neck which hosts a variety of neoplastic, vascular, infectious, inflammatory, and developmental pathologies. Evaluation of its intricate anatomy requires dedicated and complementary imaging modalities of MRI and CT. This article will provide a brief review of the anatomy of the central skull base, followed by an overview of common pathologies encountered in this region and their characteristic radiological characteristics.

Diagnosis of Skull Base Osteomyelitis

Skull base osteomyelitis (SBO) is an infection of the temporal, sphenoid, or occipital bone that can be a challenge to diagnose because of its nonspecific symptoms, long clinical course, and radiologic findings that mimic those of other entities. The authors review this unusual infection on the basis of six proven cases. The diagnosis of SBO should be made according to four points: a high index of clinical suspicion, radiologic evidence of infection, repeated biopsies that are negative for malignancy, and positive results of microbiologic tests. SBO typically manifests clinically in patients with diabetes and recurrent otitis externa; the infection usually extends inferiorly to the compact bone of the infratemporal fossa, affecting the lower cranial nerve foramina. Several image-based techniques should be used to diagnose SBO. CT is the best option for evaluating bone erosion and demineralization, MRI can help delineate the anatomic location and extent of disease, and nuclear imaging is useful for confirming bone infection with high sensitivity. However, the standard diagnostic procedure for SBO is for patients to undergo repeated biopsies to rule out malignancy, with histopathologic signs of infection and detection of microorganisms in the biopsied bone or soft tissue indicating SBO. The ability to diagnose SBO can be increased by identifying patients at risk, recognizing the most important causes and routes of infection, describing the main radiologic findings, and always considering the differential diagnosis. ^©RSNA, 2021.

An Intracerebral Type of Cranial Chondroma

The vast majority of intracranial chondromas are located in the base of the cranium. Their presentation as an intracerebral neoplasm is considered to be extremely rare. A previously healthy 45-year-old man experienced recurrent seizure attacks over a period of 6 months. Imaging studies of the brain revealed an ovoid and calcified mass which involve the cortex in the left frontal lobe. Intraoperatively, the mass had no adhesion to the dura and arachnoid membrane. The tumor was completely removed and the final diagnosis was intracerebral chondroma. The patient remained free of disease over the period of 18-years follow-up. This communication adds an unusual case to the literature on the chondroma that expressed in the form of an intra-axial space-occupying lesion in the frontal lobe.

Intracranial Dural Parafalcine Chondroma: Case Report and Systematic Review of the Literature

Intracranial chondromas are rare, benign neoplasms representing only 0.2%-0.3% of neoplastic intracranial lesions. They commonly originate from the skull base but can infrequently arise from the falx, convexity dura, or ventricular ependyma. Diagnosis requires histopathologic confirmation, as patients present with nonspecific symptoms related to mass effect, and imaging characteristics often resemble meningiomas, oligodendrogliomas, and vascular malformations. We describe the case of a patient harboring a parafalcine dural chondroma that was discovered incidentally and was managed surgically at our institution. We also provide a systematic review of the literature to elucidate incidence, origin, imaging findings, surgical management approaches, and prognosis of this rare tumor.

Maffucci syndrome and intracranial chondrosarcomas: a case report featuring spontaneous resolution of sixth nerve palsy

Maffucci syndrome is a rare disease process characterized by enchondromatosis with cutaneous hemangiomatosis. We report a 20-year-old woman with Maffucci syndrome with a 5-day history of diplopia. She was found to have a left sixth nerve palsy due to a parasellar chondrosarcoma. Three weeks later, the patient's diplopia spontaneously resolved. This unusual clinical course prompted us to review frequency of sixth nerve palsy with skull base neoplasms and the phenomenon of spontaneous resolution of diplopia.

A Solitary Convexity Dural Chondroma: the Proposed Role of Diffusion-Weighted MR Imaging in the Differential Diagnosis of Intracranial Chondroma and Meningioma. A Case Report

Chondromas arising from the dura mater are rare intracranial tumors. We describe a case of intracranial chondroma originating from the durra mater of the convexity, mimicking a meningioma. The neuroradiological and surgical findings are described. The diagnostic clues for the differential diagnosis between chondromas and meningiomas are discussed and reviewed.

Chondromas of the falx cerebri and dural convexity: report of two cases and review of the literature

Intracranial chondromas usually arise from the base of the skull. They rarely originate from the convexity dura and falx. Here we describe two cases of intracranial chondroma located at the convexity dura and falx, discuss the genesis, radiologic, histologic features and review the literature.

From the archives of the AFIP: imaging of primary chondrosarcoma: radiologic-pathologic correlation

Chondrosarcoma is a malignant tumor that produces cartilage matrix, and lesions that arise de novo are called primary. Primary chondrosarcoma is the third most common primary malignant tumor of bone, constituting 20%-27% of all primary malignant osseous neoplasms. There are numerous types of primary chondrosarcomas, including conventional intramedullary, clear cell, juxtacortical, myxoid, mesenchymal, extraskeletal, and dedifferentiated. The conventional intramedullary chondrosarcoma is the most frequent type, and it most commonly involves the long bones or pelvis in up to 65% of cases. Although the pathologic appearance varies with specific lesion type, chondrosarcomas grow with lobular type architecture, and these hyaline cartilage nodules demonstrate high water content and peripheral enchondral ossification. Imaging features directly reflect this pathologic appearance, and the various subtypes often show distinctive features. Radiographic findings often suggest the diagnosis of chondrosarcoma because of identification of typical "ring-and-arc" chondroid matrix mineralization (representing the enchondral ossification) and aggressive features of deep endosteal scalloping and soft-tissue extension. These latter features are usually best assessed, as is lesion staging, with computed tomography (CT) or magnetic resonance (MR) imaging. CT is optimal to detect the matrix mineralization, particularly when it is subtle or when the lesion is located in anatomically complex areas. Both CT and MR imaging depict the high water content of these lesions as low attenuation and very high signal intensity with T2-weighting, respectively. Understanding and recognizing the spectrum of appearances of the various types of primary chondrosarcoma allow improved patient assessment and are vital for optimal clinical management including diagnosis, biopsy, staging, treatment, and prognosis.