Imaging of Skull Base Tumors

Imaging of the skull base and orbital tumors

The skull base and orbit have complicated anatomical structures where various tumors can occur. The tumor may present with neurological symptoms; however, its diagnosis is clinically difficult owing to accessibility issues. Therefore, diagnostic imaging is crucial in assessing tumors in the skull base and orbit and guiding subsequent management. Notably, some tumors have a predilection for a specific site of origin, and identifying the site of origin on imaging can help narrow the differential diagnosis. At the skull base, chordomas typically occur in the clivus, chondrosarcomas in the paramedian areas, paragangliomas in the jugular foramen, neurogenic tumors, and perineural spread in the neural foramen. Among orbital tumors, cavernous hemangiomas usually occur in the intraconal space, and pleomorphic adenomas and adenoid cystic carcinomas occur in the lacrimal glands. Some skull base and orbital tumors exhibit distinctive imaging features. Chordomas and chondrosarcomas of the skull base show high signal intensities on T2-weighted images, with chondrosarcomas often displaying cartilaginous calcifications. Paragangliomas are characterized by their hypervascular nature. In the orbit, cavernous hemangiomas and pleomorphic adenomas present unique dynamic patterns. Immunoglobulin G4-related disease forms lesions along the nerves. Identifying the tumor origin and its imaging characteristics can help narrow the differential diagnosis of skull base and orbital tumors.

An Exceptional Case of Garcin Syndrome Mimicking Bell's Palsy in Advanced Non-Small Cell Lung Carcinoma

Garcin syndrome is an exceptional clinical condition characterized by progressive multiple ipsilateral cranial nerve involvement which is caused by malignant osteoclastic lesion at skull base. We report a rare case of Garcin syndrome which was misdiagnosed as Bell's palsy. A 69-year-old lady, presented with generalized headache and right facial nerve palsy in which progressively worsened even after treatment with corticosteroid. Computed tomography (CT) brain showed skull base erosion suggesting tuberculosis or metastatic lesion. Mass at the left hilar region was seen from her chest x-ray which raise suspicion of lung malignancy after tuberculosis has been ruled out. A month later, she developed worsening right facial nerve palsy followed by multiple cranial nerve involvement on the ipsilateral side. CT staging revealed features of lung malignancy with loco-regional and distant metastases to liver and spine. Histopathological diagnosis of non-small cell lung carcinoma was established after biopsy during bronchoscopy.

Artificial Intelligence-Assisted Stimulated Raman Histology: New Frontiers in Vibrational Tissue Imaging

Frozen section biopsy, introduced in the early 1900s, still remains the gold standard methodology for rapid histologic evaluations. Although a valuable tool, it is labor-, time-, and cost-intensive. Other challenges include visual and diagnostic variability, which may complicate interpretation and potentially compromise the quality of clinical decisions. Raman spectroscopy, with its high specificity and non-invasive nature, can be an effective tool for dependable and quick histopathology. The most promising modality in this context is stimulated Raman histology (SRH), a label-free, non-linear optical process which generates conventional H&E-like images in short time frames. SRH overcomes limitations of conventional Raman scattering by leveraging the qualities of stimulated Raman scattering (SRS), wherein the energy gets transferred from a high-power pump beam to a probe beam, resulting in high-energy, high-intensity scattering. SRH's high resolution and non-requirement of preprocessing steps make it particularly suitable when it comes to intrasurgical histology. Combining SRH with artificial intelligence (AI) can lead to greater precision and less reliance on manual interpretation, potentially easing the burden of the overburdened global histopathology workforce. We review the recent applications and advances in SRH and how it is tapping into AI to evolve as a revolutionary tool for rapid histologic analysis.

Preoperative Diagnosis of a Central Skull Base Giant Schwannoma From Tumoral Microhemorrhages Visualized on Susceptibility-Weighted Imaging

A 64-year-old female presented with extensive osseous erosion of the central skull base from a large tumor, which was evaluated with a combination of CT and MRI. Susceptibility-weighted imaging (SWI) aided the correct preoperative diagnosis of giant skull base schwannoma by demonstrating intratumoral microhemorrhages, later confirmed on histology. Other imaging features on CT and MRI were not helpful to identify the schwannoma in this case.

Intraventricular schwannomas: A case report and a literature review

Intraventricular schwannomas are extremely rare, typically benign tumors originating from Schwann cells, which are not normally found within the ventricular system. Their presence challenges conventional understanding of tumor origins and complicates diagnosis and management. We report the case of a 19-year-old female presenting with a drop attack and headache, with no significant medical history. MRI revealed a heterogeneously enhancing lesion in the right lateral ventricle. Differential diagnoses included malignant tumors; however, histopathological examination post-surgical resection confirmed an intraventricular schwannoma. Postoperative outcomes were favorable, with successful CSF diversion via a right occipital ventriculoperitoneal shunt for isolated right temporal hydrocephalus. This case is notable for its atypical presentation in a young patient, challenging the conventional understanding that intraventricular schwannomas primarily affect older individuals. In addition, the correct diagnosis and successful management of a rare intraventricular schwannoma underscores the importance of considering this rare diagnosis in patients with nonspecific neurological symptoms and intraventricular lesions. This case, alongside the literature review, enriches the body of evidence on intraventricular schwannomas, highlighting the critical role of surgical intervention and the need for a comprehensive diagnostic approach.

A Multidisciplinary Skull Base Board for Tumour and Non-Tumour Diseases: Initial Experiences

The skull base is the area where various cancerous and non-cancerous diseases occur and represents the intersection of several medical fields. The key is an integrated treatment by specialists of multiple disciplines. We prospectively analysed patients with a skull base disease between August 2022 and 2023 and presented to the Multidisciplinary Skull Base Board (MDT-SB), which takes place once a month hybridly (in-person and remotely). Thirty-nine patients (median age of 58.2 years) were included, of which twelve (30.8%) had a benign tumour, twelve (30.8%) had a malignant tumour, five had an infection (12.8%), and ten (25.6%) had other diseases. For each patient, at least two otorhinolaryngologists, a neurosurgeon, and a neuroradiologist, as well as an infectious disease specialist, a paediatrician, an oculoplastic surgeon, a maxillofacial surgeon, and a pathologist were involved in 10%, 8%, 8%, 3%, and 3% of cases, respectively. In fifteen patients (38%), the MDT-SB suggested surgical treatment; in fourteen (36%), radiological follow-ups; in five (13%), non-surgical treatments; in two, conservative treatments (5%); in two (5%), surgical and conservative treatments; and in one (3%), a biopsy. Non-cancerous and cancerous diseases of the skull base in adults and children should be presented to the MDT-SB, which consists of at least an otolaryngologist, a neurosurgeon, and a neuroradiologist.

A Rare Case of Benign Long-Standing Ecchordosis Physaliphora

Ecchordosis physaliphora (EP) is a rare benign lesion arising from embryonic notochordal remnants, typically located in the retroclival region. This case report presents a 46-year-old male patient experiencing intermittent headaches and occipital pain. Imaging revealed a well-defined, smoothly corticated bony lesion on the left side of the clivus, accompanied by a characteristic bony stalk devoid of any aggressive features. A review of the patient's medical records indicated stable imaging findings of the lesion over six years. Clinicians and radiologists should be familiar with EP as a benign entity and differentiate it from aggressive pathologies.