Current Management and Image Review of Skull Base Chordoma: What the Radiologist Needs to Know

Skull Base Chordoma and Chondrosarcoma: Neuroradiologist's Guide to Diagnosis, Surgical Management, and Proton Beam Therapy

Skull base chordomas and chondrosarcomas are distinct types of rare, locally aggressive mesenchymal tumors that share key principles of imaging investigation and multidisciplinary care. Maximal safe surgical resection is the treatment choice for each, often via an expanded endoscopic endonasal approach, with or without multilayer skull base repair. Postoperative adjuvant radiation therapy is frequently administered, usually with particle therapy such as proton beam therapy (PBT). Compared with photon therapy, PBT enables dose escalation while limiting damage to dose-limiting neurologic structures, particularly the brainstem and optic apparatus, due to energy deposition being delivered at a high maximum with a rapid decrease at the end of the penetration range (Bragg peak phenomenon). Essential requirements for PBT following gross total or maximal safe resection are tissue diagnosis, minimal residual tumor after resection, and adequate clearance from PBT dose-limiting structures. The radiologist should understand surgical approaches and surgical techniques, including multilayer skull base repair, and be aware of evolution of postsurgical imaging appearances over time. Accurate radiologic review of all relevant preoperative imaging examinations and of intraoperative and postoperative MRI examinations plays a key role in management. The radiology report should reflect what the skull base surgeon and radiation oncologist need to know, including distance between the tumor and PBT dose-limiting structures, tumor sites that may be difficult to access via the endoscopic endonasal route, the relationship between intradural tumor and neurovascular structures, and tumor sites with implications for postresection stability. ©RSNA, 2024 Supplemental material is available for this article.

Current knowledge of antisense long non-coding RNA in the occurrence and prognosis of skull base tumors

Antisense long non-coding RNA (AS-lncRNA) represents a novel class of RNA molecules. In recent years, it has been discovered that AS-lncRNAs play crucial roles in various biological processes, particularly in the onset and progression of tumors. Skull base tumors, originating from the base of the brain, exhibit specific expression patterns of AS-lncRNA which correlate significantly with clinical characteristics. This makes AS-lncRNA a promising candidate as a tumor marker. Functional studies have revealed that AS-lncRNAs can regulate gene expression by acting as miRNA sponges and interacting with RBPs. Consequently, they play pivotal roles in tumor cell cycle, apoptosis, angiogenesis, invasion, and metastasis processes. Further exploration into the mechanisms of AS-lncRNA in tumors holds substantial theoretical significance for deeper insights into the etiology, pathogenesis, and RNA dynamics of skull base tumors. Moreover, AS-lncRNA could serve as molecular markers or potential targets for early diagnosis. Their potential extends to efficacy assessment, prognosis prediction, and gene therapy, suggesting broad clinical applications. In summary, AS-lncRNA emerges as a promising molecular marker implicated in the onset and progression of skull base tumors.

Chordoma: demographics and survival analysis with a focus on racial disparities and the role of surgery, a U.S. population-based study

BACKGROUND

Chordoma is a rare malignant tumor of notochordal origin that may appear anywhere in the axial skeleton from the skull base to the sacrum. This study presents findings from a large database query to highlight the demographic, clinical, and pathological factors, prognosis, and survival of chordomas.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) data based was used to identify patients with a "chordoma" diagnosis from 200 to 2018.

RESULTS

In a total of 1600 cases, the mean age at diagnosis was 54.47 years (standard deviation, SD ± 19.62 years). Most cases were male (57.1%) and white (84.5%). Tumor size was found to be > 4 cm in 26% of cases. Histologically, 33% with known features had well-differentiated Grade I tumors, and 50.2% of the tumors were localized. Metastasis at the time of to the bone, liver, and lung was observed at a rate of 0.5%, 0.1%, and 0.7%, respectively. The most common treatment received was surgical resection (41.3%). The overall 5-year overall survival observed was 39% (confidence interval, CI 95% 37-41; p = 0.05) with patients who received surgery having a 5-year survival rate of 43% (CI 95% 40-46; p = 0.05). Multivariate analysis showed independent factors that contributed to worse prognosis chemotherapy only as a treatment modality and no surgery as a treatment modality.

CONCLUSION

Chordomas are more common in white males and appear between the 5th and 6th decades of life. Factors that contributed to a worse prognosis were Asian, Pacific Islander, American Indian, or Alaska Native races.

Imaging of pituitary tumors: an update with the 5th WHO Classifications-part 2. Neoplasms other than PitNET and tumor-mimicking lesions

Many types of tumors can develop in the pituitary gland. In the recently revised 5th editions of the World Health Organization (WHO) classifications (2021 WHO Classification of Central Nervous System Tumors and the 2022 WHO Classification of Endocrine and Neuroendocrine Tumors), various changes have been made to the tumors other than pituitary neuroendocrine tumor (PitNET)/pituitary adenoma, as well as PitNET. Adamantinomatous craniopharyngioma and papillary craniopharyngioma are now considered separate tumors in the 5th edition of the WHO classification. Tumors positive for thyroid transcription factor 1, a marker of posterior pituitary cells, are now grouped together in the pituicyte tumor family in the 5th edition of the WHO classification of Endocrine and Neuroendocrine Tumors. Poorly differentiated chordoma is newly listed in the 5th edition of the WHO Classification of Endocrine and Neuroendocrine Tumors. In this paper, we present the latest WHO classification of pituitary tumors (adamantinomatous craniopharyngioma, papillary craniopharyngioma, pituitary blastoma, pituicyte tumor family, tumors of pituitary origin other than those of the pituicyte tumor family, germinoma, meningioma, chordoma, metastatic tumors, lymphoma, and pituitary incidentaloma), review diseases requiring differentiation from tumors (pituitary abscess, hypophysitis, pituitary hyperplasia, Rathke's cleft cyst, arachnoid cyst, and aneurysm), and discuss diagnoses based on imaging findings.

Proton Radiotherapy for Skull-Base Malignancies

Proton therapy (PT) is a form of highly conformal external-beam radiotherapy used to mitigate acute and late effects following radiotherapy. Indications for treatment include both benign and malignant skull-base and central nervous system pathologies. Studies have demonstrated that PT shows promising results in minimizing neurocognitive decline and reducing second malignancies with low rates of central nervous system necrosis. Future directions and advances in biologic optimization may provide additional benefits beyond the physical properties of particle dosimetry.