The utility of disc space and vertebral body specimens cell count differential for the diagnosis of native vertebral osteomyelitis: a prospective cohort study.

BACKGROUND: Diagnostic methods for native vertebral osteomyelitis (NVO) often yield inconclusive results. Image-guided spine biopsies for culture are specific but diagnose NVO in only 50% of cases. Pre-exposure to antimicrobials further reduces diagnostic yield. Our study assesses the value of neutrophil percentage in disc space fluid and vertebral body (DS/VB) samples for diagnosing NVO. METHODS: Adults referred for spine biopsy at Mayo Clinic from August 2022 to September 2023 were consented and enrolled at the time of biopsy. Following routine specimen collection, the biopsy needle was rinsed in saline into an EDTA tube for cell analysis. NVO diagnosis required organism identification in spine tissue or blood and/or positive histopathology, and consistent symptoms and imaging. RESULTS: Sixty-eight patients were prospectively enrolled, comprising 14 with NVO and 54 with alternative diagnoses. The median biopsy sample polymorphonuclear (PMN) percentage for NVO patients was 80.5% (IQR 72.5-85.2), compared to 64.5% (IQR 54.0-69.0) for those without NVO (p < 0.001). Nine (64.3%) NVO patients received antibiotics within 10 days prior to spine biopsy. As a continuous measure, PMN differential showed a moderately strong ability in classifying NVO status with an area under ROC curve of 0.795; an optimal point on the curve of 71.5% corresponded to a sensitivity of 78.6%, specificity of 79.6%, negative predictive value of 93.5% and positive predictive value of 50.0%. CONCLUSION: PMN differential in DS/VB biopsies may serve as an effective diagnostic tool in the evaluation of patients with NVO particularly in ambiguous cases with an initially negative spine biopsy. Future efforts will aim to implement these findings within routine clinical practice.

Clinical and Imaging Outcomes of Surgically Repaired Cerebrospinal Fluid-Venous Fistulas Identified by Lateral Decubitus Digital Subtraction Myelography.

OBJECTIVE: To describe clinical and radiographic outcomes of surgical repair of cerebrospinal fluid-venous fistula (CVF), an increasingly recognized cause of spontaneous intracranial hypotension that is poorly responsive to epidural blood patch (EBP). METHODS: Retrospective review identified adult patients who had lateral decubitus digital subtraction myelography indicative of cerebrospinal fluid leak at Mayo Clinic between November 2018 and February 2020, with clearly localized CVF, followed by surgical treatment. Patients without available imaging before or after surgery were excluded. History of EBP and clinical response to EBP were evaluated along with surgical outcomes. RESULTS: Of 25 patients with CVF who met protocol criteria and were included in the data analysis, 22 (88%) received EBP, but clinical benefit lasting ≥4 weeks occurred in only 2 of 22 (9%). Headache was the most prominent preoperative feature among patients (24/25; 96%). Following surgery, 18 of 24 (75%) patients had complete headache improvement, 4 (17%) had partial improvement, and 2 (8%) had no improvement. Ten of 25 (40%) patients reported cognitive disturbance at baseline; at follow-up, 5 of 10 (50%) had complete improvement, 3 (30%) had partial improvement, and 2 (20%) had no improvement. On postoperative brain magnetic resonance imaging, 6 of 25 (24%) patients had complete resolution of findings by Bern score criteria, 18 (72%) showed partial improvement, and 1 (4%) patient showed no improvement. Adverse events were minor and included surgical site pain and paresthesias. CONCLUSIONS: Surgical repair of CVF resulted in improvements in headache and other symptoms, with few side effects.

Evaluation of Long-Term Follow-Up in Ecchordosis Physaliphora versus Chordoma.

OBJECTIVE: Ecchordosis physaliphora (EP) is a non-neoplastic notochord remnant with limited literature. We present a review on surgically resected clival EP to evaluate if available follow-up is adequate to distinguish EP from chordomas. METHODS: A systematic literature review was completed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Case reports or series of adults with histopathologic and radiographic findings of surgically resected EP were included. Articles including pediatric patients, systematic reviews, chordomas, and without microscopic or radiographic confirmation, or the surgical approach, were excluded. Corresponding authors were contacted twice to further evaluate outcomes. RESULTS: Eighteen articles were included (n = 25 patients; mean age 47.5 years ± 12.6 [standard deviation] months). All patients had symptomatic, surgically resected EP, with cerebrospinal fluid leak or rhinorrhea the most common symptom (48%). All but 3 had gross total resection, with endoscopic endonasal transsphenoidal transclival the most common approach (80%). All but 3 reported immunohistochemistry findings, with physaliphorous cells the most common. All but 5 patients had definitive follow-up (80%), with average of 19.5 ± 17.2 months. One corresponding author reported longer-term follow-up for 1 patient (57 months). No recurrence or malignant transformation was reported. Mean time to clival chordoma recurrence (53.9 ± 26.8 months) was also evaluated in a review of 8 studies. CONCLUSIONS: Mean follow-up for resected EP was almost 3 times shorter than mean time to recurrence of chordomas. Available literature is likely inadequate to confirm the suspected benign nature of EP especially in reference to chordoma, precluding treatment and follow-up recommendations.

Efficacy of epidural blood patching or surgery in spontaneous intracranial hypotension: an evidence map protocol.

BACKGROUND: Spontaneous intracranial hypotension (SIH) is a debilitating disorder caused by non-iatrogenic spinal cerebrospinal fluid leaks. SIH is increasingly recognized as an important treatable cause of secondary headaches. Treatment involves either epidural blood patching or surgery, which have considerable differences in their adverse event rates, recovery times, and cost. The objective of this evidence map is to understand the breadth of studies that investigate SIH treatment efficacy and to identify knowledge gaps to inform future research. METHODS: This review will consider experimental, observational, and systematic review studies that assess the efficacy of epidural blood patching and surgery for the treatment of patients with SIH. Individual case studies, clinical guidelines, editorials, protocols, and studies that do not assess an intervention will not be included. English language studies will be included without limitation based on the date of publication. Databases to be searched include MEDLINE® (via Ovid), EMBASE (via Elsevier), and Web of Science™ (via Clarivate). Study selection will be performed independently by two investigators with extracted data to include study type, the number of patients included, patient descriptors, intervention characteristics, and outcome measure used. Data will be presented through a narrative summary aided by tabular and graphical formats in a manner that aligns with the objective of the evidence mapping review. DISCUSSION: The overarching goal of this evidence map is to provide an improved understanding of the breadth of studies investigating SIH treatment efficacy in the literature and to thereby identify knowledge gaps that can inform future research directions. TRIAL REGISTRATION: OSF Registry https://osf.io/nwju7 .

Manifestations of radiation toxicity in the head, neck, and spine: An image-based review.

BACKGROUND AND PURPOSE: Radiation therapy is an important component of treatment in patients with malignancies of the head, neck, and spine. However, radiation to these regions has well-known potential side effects, many of which can be encountered on imaging. In this manuscript, we review selected radiographic manifestations of therapeutic radiation to the head, neck, and spine that may be encountered in the practice of radiology. METHODS: We conducted an extensive literature review of known complications of radiation therapy in the head, neck, and spine. We excluded intracranial and pulmonary radiation effects from our search. We selected complications that had salient, recognizable imaging findings. We searched our imaging database for illustrative examples of these complications. RESULTS: Based on our initial literature search and imaging database review, we selected cases of radiation-induced tumors, radiation tissue necrosis (osteoradionecrosis and soft tissue necrosis), carotid stenosis and blowout secondary to radiation, enlarging thyroglossal duct cysts, radiation myelopathy, and radiation-induced vertebral compression fractures. CONCLUSIONS: We describe the clinical and imaging features of selected sequelae of radiation therapy to the head, neck, and spine, with a focus on those with characteristic imaging findings that can be instrumental in helping to make the diagnosis. Knowledge of these entities and their imaging findings is crucial for accurate diagnosis. Not only do radiologists play a key role in early detection of these entities, but many of these entities can be misinterpreted if one is not familiar with them.

MRI enhancement patterns in 28 cases of clival chordomas.

Clival chordomas are classically thought of as locally aggressive tumors of the skull base and differentiate themselves from their benign counterparts by demonstrating moderate to marked contrast enhancement, reported as 95-100% in prior studies. The purpose of this review was to evaluate the imaging characteristics of lesions from a single institution classified as clival chordomas with an emphasis of highlighting lesions that do not follow the prevalent current description for chordoma. We searched our institutional databases for all patients with pathologically proven clival chordomas from 1997 to 2017 who had pre-operative imaging available. The images were evaluated for degree of contrast enhancement, MRI signal characteristics, osseous involvement, location, aggressiveness of appearance, and presence of calcifications. 28 cases were identified that had preoperative imaging available for review. Over half of the patients demonstrated either no/minimal (11/28, 39%) or mild enhancement (7/28, 25%). The remaining cases demonstrated moderate (4/28, 14%) and marked enhancement (6/28, 21%). The 4 lesions measuring less than 20 mm all had mild to minimal/no enhancement and lacked aggressive features on CT. Our experience finds that over half (64%) of clival chordomas will demonstrate mild or no enhancement at all. These findings suggest that the lack of MRI contrast enhancement should not be synonymous with a benign clival mass.

Subdural spinal metastases detected on CT myelography: A case report and brief review.

Spinal metastases are most commonly osseous and may extend to the epidural space. Less commonly, spinal metastases can be subdural, leptomeningeal, or intramedullary. Among these, subdural metastases are the most rare, with few reported cases. While these lesions are now almost exclusively detected on MRI, they can rarely be apparent on other modalities. It is important to recognize subdural metastases on any modality, because they have a significant impact on patient prognosis and treatment. We report a case of renal cell carcinoma in a 68-year-old male initially presenting with subdural metastases detected on CT myelography, with subsequent confirmation by MRI. The case illustrates, to our knowledge, the first example of subdural metastatic disease seen on CT myelography.

Diagnostic yield, accuracy, and complication rate of CT-guided biopsy for spinal lesions: a systematic review and meta-analysis.

BACKGROUND: CT-guided biopsy is a commonly used diagnostic procedure for spinal lesions. This meta-analysis aims to investigate its diagnostic performance and complications, as well as factors influencing outcomes. METHODS: A systematic review of the literature was performed to identify studies reporting outcomes of CT-guided biopsies for spinal lesions. Diagnostic yield (ie, the rate of procedures resulting in a specific pathological diagnosis) and diagnostic accuracy (ie, the rate of procedures resulting in the correct diagnosis) were the primary outcomes of interest. Complications following biopsy procedures were also included. RESULTS: Thirty-nine studies with 3917 patients undergoing 4181 procedures were included. Diagnostic yield per procedure was 91% (95% CI 88% to 94%) among 3598 procedures. The most common reason for non-diagnostic biopsies was inadequacy of sample. No difference in diagnostic yield between different locations and between lytic, sclerotic, and mixed lesions was found. Diagnostic yield did not differ between procedures using ≤13G and ≥14G needles. Diagnostic accuracy per procedure was 86% (95% CI 82% to 89%) among 3054 procedures. Diagnostic accuracy among 2426 procedures that yielded a diagnosis was 94% (95% CI 92% to 96%). Complication rate was 1% (95% CI 0.4% to 1.9%) among 3357 procedures. Transient pain and minor hematoma were the most common complications encountered. CONCLUSION: In our meta-analysis of 39 studies reporting diagnostic performance and complications of CT-guided biopsy, we found a diagnostic yield of 91% and diagnostic accuracy of 86% with a complication rate of 1%. Diagnostic yield did not differ between different locations, between lytic, sclerotic and mixed lesions, and between wide- and thin-bore needles.

Impact of flow pattern, body mass index, and age on intraprocedural fluoroscopic time and radiation dose during sacroiliac joint injections.

PURPOSE: Understanding all factors that may impact radiation dose and procedural time is crucial to safe and efficient image-guided interventions, such as fluoroscopically guided sacroiliac (SI) joint injections. The purpose of this study was to evaluate the effect of flow pattern (intra- vs. periarticular), patient age, and body mass index (BMI) on radiation dose and fluoroscopy time. METHODS: A total of 134 SI joint injections were reviewed. Injectate flow pattern, age, and BMI were analyzed in respect to fluoroscopy time (minutes), radiation dose (kerma area product (KAP); µGy m2), and estimated skin dose (mGy). RESULTS: BMI did not affect fluoroscopy time, but increased BMI resulted in significantly higher skin and fluoroscopy doses (p < 0.001). There was no association between fluoroscopy time and flow pattern. Higher skin dose was associated with intraarticular flow (p = 0.0086), and higher KAP was associated with periarticular flow (p = 0.0128). However, the odds ratios were close to 1. There was no significant difference between fluoroscopy time or dose based on patient age. CONCLUSION: Increased BMI had the largest impact on procedural radiation dose and skin dose. Flow pattern also showed a statistically significant association with radiation dose and skin dose, but the clinical difference was small. Proceduralists should be aware that BMI has the greatest impact on fluoroscopy dose and skin dose during SI joint injections compared to other factors.

Intracranial long-term complications of radiation therapy: an image-based review.

BACKGROUND AND PURPOSE: Radiation therapy is commonly utilized in the majority of solid cancers and many hematologic malignancies and other disorders. While it has an undeniably major role in improving cancer survival, radiation therapy has long been recognized to have various negative effects, ranging from mild to severe. In this manuscript, we review several intracranial manifestations of therapeutic radiation, with particular attention to those that may be encountered by radiologists. METHODS: We conducted an extensive literature review of known complications of intracranial radiation therapy. Based on this review, we selected complications that had salient, recognizable imaging findings. We searched our imaging database for illustrative examples of these complications, focusing only on patients who had a history of intracranial radiation therapy. We then selected cases that best exemplified expected imaging findings in these entities. RESULTS: Based on our initial literature search and imaging database review, we selected cases of radiation-induced meningioma, radiation-induced glioma, cavernous malformation, enlarging perivascular spaces, leukoencephalopathy, stroke-like migraine after radiation therapy, Moyamoya syndrome, radiation necrosis, radiation-induced labyrinthitis, optic neuropathy, and retinopathy. Although retinopathy is not typically apparent on imaging, it has been included given its clinical overlap with optic neuropathy. CONCLUSIONS: We describe the clinical and imaging features of selected sequelae of intracranial radiation therapy, with a focus on those most relevant to practicing radiologists. Knowledge of these complications and their imaging findings is important, because radiologists play a key role in early detection of these entities.

Giant torus mandibularis causing submandibular duct obstruction and sialadenitis.

Torus mandibularis is a benign osseous overgrowth arising from the lingual surface of the mandible. It is a common, incidental finding on imaging due to its relatively high prevalence. In the majority of cases, mandibular tori are asymptomatic. We report a novel presentation of a giant torus mandibularis causing bilateral obstruction of the submandibular ducts and consequent sialadenitis. Our patient presented with progressive pain centered in the floor of his mouth and had bilateral submandibular glandular enlargement on exam. Computed tomography showed a giant right torus mandibularis, which was causing obstruction and dilation of the bilateral submandibular ducts. Although conservative management was attempted, he ultimately underwent surgical resection of his torus with symptomatic improvement. This patient highlights a novel complication of torus mandibularis and illustrates successful treatment. Though not previously described, this complication may be underreported and should be considered in the appropriate clinical setting.

Deep neural network to locate and segment brain tumors outperformed the expert technicians who created the training data.

Purpose: Deep learning (DL) algorithms have shown promising results for brain tumor segmentation in MRI. However, validation is required prior to routine clinical use. We report the first randomized and blinded comparison of DL and trained technician segmentations. Approach: We compiled a multi-institutional database of 741 pretreatment MRI exams. Each contained a postcontrast T1-weighted exam, a T2-weighted fluid-attenuated inversion recovery exam, and at least one technician-derived tumor segmentation. The database included 729 unique patients (470 males and 259 females). Of these exams, 641 were used for training the DL system, and 100 were reserved for testing. We developed a platform to enable qualitative, blinded, controlled assessment of lesion segmentations made by technicians and the DL method. On this platform, 20 neuroradiologists performed 400 side-by-side comparisons of segmentations on 100 test cases. They scored each segmentation between 0 (poor) and 10 (perfect). Agreement between segmentations from technicians and the DL method was also evaluated quantitatively using the Dice coefficient, which produces values between 0 (no overlap) and 1 (perfect overlap). Results: The neuroradiologists gave technician and DL segmentations mean scores of 6.97 and 7.31, respectively ( p < 0.00007 ). The DL method achieved a mean Dice coefficient of 0.87 on the test cases. Conclusions: This was the first objective comparison of automated and human segmentation using a blinded controlled assessment study. Our DL system learned to outperform its "human teachers" and produced output that was better, on average, than its training data.

Spinal Cord Cavernous Malformations: MRI Commonly Shows Adjacent Intramedullary Hemorrhage.

BACKGROUND AND PURPOSE: There is a relative paucity of radiology literature on spinal cord cavernous malformations (SCMs). We hypothesized that the classic MRI features of cavernous malformations are not highly prevalent. The purpose was to review MR imaging findings of SCMs with a focus on prevalence of hemorrhagic features, including adjacent intramedullary hemorrhage at initial presentation. METHODS: In this single-institution study, 78 SCMs in 76 patients diagnosed on imaging/pathology were retrospectively evaluated for size, location, cord expansion, exophytic component, popcorn morphology, signal characteristics, including T1 weighted (T1w) and T2w rims, blood-fluid levels, and adjacent intramedullary hemorrhage. Intramedullary hemorrhage was defined as centrally and/or eccentrically located linear or flame shaped non-edematous signal abnormality extending longitudinally away from SCMs, distinct from lesional rim. RESULTS: Sixty-three percent (49/78) of SCMs measured <1 cm in length, 78% (61/78) extended to the cord surface, 65% (51/78) were expansile, and 32% (25/78) were exophytic. Popcorn morphology was seen in 15% (12/78) on T1w and 22% (17/78) on T2w. Internal blood-fluid levels were evident in 4% (3/78). Sixty-nine percent (54/78) showed T2w hypointense rims; the T2w rim was complete/near-complete in 37% (29/78). A rim on T1w was visible in 49% (38/78); this was hyperintense in 58% (22/38). Adjacent intramedullary hemorrhage was seen in 45/78 (58%), was most commonly bidirectional in 67% (30/45) and eccentric in 68% (30/44). Cord edema was seen in 22% (17/78); 53% (9/17) also demonstrated intramedullary hemorrhage with edema. CONCLUSIONS: The classically described popcorn morphology, internal blood-fluid levels, and complete/near-complete T2w hypointense rims are often absent on MRIs in SCMs. Adjacent intramedullary hemorrhage is frequently present, often eccentric and bidirectional.

Dorsal cauda equina nerve root enhancement on magnetic resonance imaging due to ANNA-1-associated paraneoplastic polyneuropathy.

A 69-year-old female presented with subacute onset ascending weakness and paraesthesias. She was initially diagnosed with Guillain-Barré syndrome (GBS) based on her clinical presentation and cerebrospinal fluid (CSF) analysis showing albuminocytological dissociation. However, she was later found to have anti-neuronal nuclear antibody 1 (ANNA-1/anti-Hu)-positive CSF and was subsequently diagnosed with small-cell lung cancer. Her neurological symptoms were ultimately attributed to ANNA-1/anti-Hu-associated paraneoplastic polyneuropathy. During the course of her evaluation, she had magnetic resonance imaging findings of dorsal predominant cauda equina nerve root enhancement, which has not been previously described. The only previously reported case of cauda equina enhancement due to ANNA-1-associated polyneuropathy described ventral predominant findings. The distinction between ventral and dorsal enhancement is important, since it suggests that different patterns of nerve root involvement may be associated with this paraneoplastic syndrome. Therefore, ANNA-1-associated paraneoplastic inflammatory polyneuropathy can be considered in the differential diagnosis of cauda equina nerve root enhancement with ventral and/or dorsal predominance. This can potentially be helpful in differentiating ANNA-1 polyneuropathy from GBS, which classically has ventral predominant enhancement.

Association Between Klippel-Trenaunay Syndrome and Spontaneous Intracranial Hypotension: A Report of 4 Patients.

BACKGROUND: Klippel-Trenaunay syndrome (KTS) is associated with a wide variety of vascular and neurologic abnormalities, including venolymphatic malformations. A recent report postulated that patients with KTS may also be predisposed to spontaneous intracranial hypotension. We reviewed brain magnetic resonance imaging from 67 patients with KTS and unexpectedly noted findings of cerebrospinal fluid (CSF) hypotension in 4 of them. CASE DESCRIPTION: Patients included a 39-year-old woman with episodic orthostatic headaches, a 62-year-old woman with orthostatic headaches and light-headedness, a 14-year-old girl with a history of headaches for years, and an asymptomatic 20-year-old man. All 4 patients had known KTS, and all had brain magnetic resonance imaging done during their evaluation showing evidence of CSF hypotension. The first 2 patients also had spine imaging demonstrating paraspinal and/or epidural venolymphatic malformations. The second patient had a meningeal diverticulum and underwent surgical repair with intraoperative evidence of a CSF leak. CONCLUSIONS: Patients with KTS have an increased incidence of CSF hypotension. While it is possible that intrinsic dural weakness may be responsible for this association, we hypothesize that these patients are also predisposed to developing CSF venous fistulas. Paraspinal and epidural venolymphatic malformations have been described in multiple patients with CSF venous fistulas. Such malformations were present in 2 of our 4 patients who underwent spine imaging. Patients with KTS with orthostatic headaches may benefit from brain and spine magnetic resonance imaging to assess for evidence of CSF hypotension and venolymphatic malformations. Decubitus digital subtraction myelography may also have a role in these patients if CSF venous fistulas are suspected.

Enlarging Perivascular Spaces Following Radiation Therapy in the Brain: A Report of 2 Cases and Literature Review.

BACKGROUND: Virchow-Robin or enlarged perivascular spaces (PVS) are benign pial-lined spaces that surround penetrating arteries and arterioles through the brain parenchyma. We present 2 cases of enlarging PVS in adults following whole-brain radiation therapy. CASE DESCRIPTION: Two patients underwent whole-brain radiation therapy for adult-onset medulloblastoma. Neither patient had enlarged PVS at the time of radiation treatment. The patients presented with PVS in the basal ganglia 6 and 8 years following the completion of radiation, respectively. One patient subsequently showed a decrease in size of PVS over time. Neither patient experienced symptoms, required surgical intervention, or had signs of tumor recurrence. CONCLUSIONS: Enlarging PVS can occur years after radiation therapy to the brain parenchyma. Recognition of these benign PVS is important so as not to mistake the changes for more sinister pathology that could lead to unnecessary intervention. Moreover, focal cystic changes more frequently seen surrounding areas of focal brain radiation therapy might represent enlarged PVS.

Headache due to spontaneous spinal cerebrospinal fluid leak secondary to cerebrospinal fluid-venous fistula: Case series.

OBJECTIVE: Cerebrospinal fluid-venous fistula is an uncommon cause of spontaneous spinal cerebrospinal fluid leak (SSCSFL). We aim to describe the clinical presentation, imaging evaluation, treatment and outcome of SSCSFL secondary to cerebrospinal fluid-venous fistula. METHODS: A retrospective review was undertaken of SSCSFL cases secondary to cerebrospinal fluid-venous fistula confirmed radiologically or intraoperatively, seen at our institution from January 1994 to March 2019. Cases with undetermined SSCSFL etiology, alternative etiology or unconfirmed fistula were excluded. RESULTS: Forty-four of 156 patients met the inclusion criteria (31 women, 13 men). Mean age of symptom onset was 52.6 years (SD 8.7, range 33-71 years). Headache was the presenting symptom in almost all, typically daily (69%), and most often in occipital/suboccipital regions. Headache character was most commonly pressure (38%), followed by throbbing/pulsing (21.4%). Orthostatic headache worsening occurred in 69% and an even greater percentage of patients (88%) reported Valsalva-induced headache exacerbation or precipitation. Headache occurred in isolation to Valsalva maneuvers in 12%. Of 37 patients with documented cerebrospinal fluid opening pressure, 13% were <6 cmH2O; 84%, 7-20 cmH2O; and one, 25 cmH2O. Fistulas were almost exclusively thoracic (95.5%). Only one patient responded definitively to epidural blood patch (EBP). Forty-two patients underwent surgery. Most improved following surgery; 48.7% were completely headache free and 26.8% had at least 50% improvement. CONCLUSION: In our series, cerebrospinal fluid-venous fistula was associated with a greater occurrence of Valsalva-induced headache exacerbation or precipitation than orthostatic headache and did not respond to EBP. Surgery provided significant improvement. Cerebrospinal fluid-venous fistula should be considered early in the differential diagnosis of Valsalva-induced ("cough") headache.

Benign notochordal cell tumor of the clivus with chordoma component: report of 2 cases.

Benign notochordal cell tumors (BNCTs) are considered to be benign intraosseous lesions of notochord origin; however, recent spine studies have suggested the possibility that some chordomas arise from BNCTs. Here, the authors describe two cases demonstrating histological features of BNCT and concomitant chordoma involving the clivus, which, to the best of the authors' knowledge, have not been previously documented at this anatomical site.An 18-year-old female presented with an incidentally discovered clival mass. Magnetic resonance imaging revealed a 2.8-cm nonenhancing lesion in the upper clivus that was T2 hyperintense and T1 hypointense. She underwent an uneventful endoscopic transsphenoidal resection. Histologically, the tumor demonstrated areas of classic chordoma and a distinct intraosseous BNCT component. The patient completed adjuvant radiation therapy. Follow-up showed no recurrence at 18 months.A 39-year-old male presented with an incidentally discovered 2.8-cm clival lesion. The nonenhancing mass was T2 hyperintense and T1 hypointense. Surgical removal of the lesion was performed through an endoscopic transsphenoidal approach. Histological analysis revealed areas of BNCT with typical features of chordoma. Follow-up did not demonstrate recurrence at 4 years.These cases document histologically concomitant BNCT and chordoma involving the clivus, suggesting that the BNCT component may be a precursor of chordoma.