SMARCB1/INI1 loss in skull base conventional chordomas: a clinicopathological and molecular analysis

Exploring perspectives on skull base chordoma management: a modified Delphi approach to consensus

OBJECTIVE

Current treatment for skull base chordomas utilizes both surgical resection and adjuvant radiation, but recent studies have demonstrated evidence that has brought the use of adjuvant radiotherapy into question. Chordomas differ greatly in molecular makeup and proliferation. These factors have led to significant variation in management across providers. We used a modified Delphi approach to work towards consensus on standardized operative definitions and evidence-based management of chordomas.

METHODS

Our multidisciplinary panel included participants representing the AANS/CNS Tumor Section and North American Skull Base Society (NASBS) with a track record of publishing on chordoma management. Our approach involved a four-step process: one statement-generation round, two voting rounds to establish consensus and refine statements, and a final external validation round by NASBS members. Anonymous voting was completed via Qualtrics surveys.

RESULTS

The statement-generation process produced 65 statements. Through the Delphi process, 36 statements reached consensus during the first round and an additional 17 were refined for further consensus in the second round. Moderate (67-80%) or strong (> 80%) consensus was achieved for 43 final statements. Forty-one items were externally validated. There was consensus that an endoscopic endonasal approach should be utilized whenever possible. They defined the tumor characteristics (molecular and cytogenic) to consider before offering adjuvant radiotherapy.

CONCLUSIONS

This modified Delphi study generated consensus on 41 statements regarding skull base chordoma management. These statements aim to shed light on the consensus among providers regarding the use of surgery, neoadjuvant radiation, adjuvant radiation, adjuvant systemic therapies, and treatment of recurrence for chordoma.

Rare Extra-Axial Chordoma of the Anteromedial Thigh: A Case Report

Chordomas are rare notochordal malignancies typically occurring in the axial skeleton. Less than 100 extra-axial chordomas have been reported. We describe a unique chordoma of the anteromedial thigh. The clinical presentation of extra-axial chordomas is highly variable; thus, recognizing this entity in the differential diagnoses of extra-axial bone/soft tissue tumors is important.

Conventional Spinal Chordomas: Investigation of SMARCB1/INI1 Protein Expression, Genetic Alterations in SMARCB1 Gene, and Clinicopathological Features in 89 Patients

The partial loss of SMARCB1/INI1 expression has recently been reported in skull base conventional chordomas, with possible therapeutic implications. We retrospectively analyzed 89 patients with conventional spinal chordomas to investigate the differences in the immunohistochemical expression of SMARCB1/INI1 and the underlying genetic alterations in the SMARCB1 gene. Moreover, we assessed the correlation of clinicopathological features (age, gender, tumor size, tumor location, surgical margins, Ki67 labelling index, SMARCB1/INI1 pattern, previous surgery, previous treatment, type of surgery, and the Charlson Comorbidity Index) with patient survival. Our cohort included 51 males and 38 females, with a median age at diagnosis of 61 years. The median tumor size at presentation was 5.9 cm. The 5-year overall survival (OS) and 5-year disease-free survival (DFS) rates were 90.8% and 54.9%, respectively. Partial SMARCB1/INI1 loss was identified in 37 (41.6%) patients with conventional spinal chordomas (27 mosaic and 10 clonal). The most frequent genetic alteration detected was the monoallelic deletion of a portion of the long arm of chromosome 22, which includes the SMARCB1 gene. Partial loss of SMARCB1/INI1 was correlated with cervical-thoracic-lumbar tumor location (p = 0.033) and inadequate surgical margins (p = 0.007), possibly due to the high degree of tumor invasiveness in this site. Among all the considered clinicopathological features related to patient survival, only tumor location in the sacrococcygeal region and adequate surgical margins positively impacted DFS. In conclusion, partial SMARCB1/INI1 loss, mostly due to 22q deletion, was detected in a significant number of patients with conventional spinal chordomas and was correlated with mobile spine location and inadequate surgical margins.

Integrated Molecular and Histological Insights for Targeted Therapies in Mesenchymal Sinonasal Tract Tumors

PURPOSE OF REVIEW

This review aims to provide a comprehensive overview of mesenchymal sinonasal tract tumors (STTs), a distinct subset of STTs. Despite their rarity, mesenchymal STTs represent a unique clinical challenge, characterized by their rarity, often slow progression, and frequently subtle or overlooked symptoms. The complex anatomy of the sinonasal area, which includes critical structures such as the orbit, brain, and cranial nerves, further complicates surgical treatment options. This underscores an urgent need for more advanced and specialized therapeutic approaches.

RECENT FINDINGS

Advancements in molecular diagnostics, particularly in next-generation sequencing, have significantly enhanced our understanding of STTs. Consequently, the World Health Organization has updated its tumor classification to better reflect the distinct histological and molecular profiles of these tumors, as well as to categorize mesenchymal STTs with greater accuracy. The growing understanding of the molecular characteristics of mesenchymal STTs opens new possibilities for targeted therapeutic interventions, marking a significant shift in treatment paradigms. This review article concentrates on mesenchymal STTs, specifically addressing sinonasal tract angiofibroma, sinonasal glomangiopericytoma, biphenotypic sinonasal sarcoma, and skull base chordoma. These entities are marked by unique histopathological and molecular features, which challenge conventional treatment approaches and simultaneously open avenues for novel targeted therapies. Our discussion is geared towards delineating the molecular underpinnings of mesenchymal STTs, with the objective of enhancing therapeutic strategies and addressing the existing shortcomings in the management of these intricate tumors.