Chondroid chordoma is a rare skull-base tumor of notochordal origin that radiologically mimics chondrosarcoma, making histopathology and immunohistochemistry essential for diagnosis. We report a 22-year-old man with progressive occipital headache, imbalance, diplopia, and tinnitus. CT and MRI revealed a destructive midline retroclival mass encasing the basilar and cavernous carotid arteries with brainstem compression. A transmaxillary–transclival approach achieved gross total resection. Histology showed physaliphorous cells within a myxoid/chondroid matrix. Immunohistochemistry demonstrated EMA, S100, and vimentin positivity with preserved INI-1 and low Ki-67 (1–2%), confirming chondroid chordoma. Postoperative MRI identified small residual tumor at the left petrous apex and cavernous sinus. The patient recovered to WHO performance status 0 except for persistent diplopia and was referred for adjuvant high-dose intensity-modulated radiotherapy (IMRT). This case illustrates the diagnostic challenge of clival chondroid chordoma, the limits of safe resection in the skull base, and the need for multidisciplinary management with high-dose conformal radiotherapy. Although historically thought less aggressive, chondroid chordoma shares the recurrence risk and long-term prognosis of conventional chordoma, warranting lifelong imaging surveillance

Chordomas are rare ectodermal bone malignancies derived from transformed notochordal remnants. Histologic variants include conventional (80%-90%), chondroid (5%-15%), and dedifferentiated (2%-8%). Because chordomas are relatively resistant to chemotherapy and radiotherapy, novel targeted agents are needed to expand treatment approaches and improve outcomes. This study analyzes the genomic landscape of chordoma and identifies potential pathogenic and druggable targets. Eighty-six tumor samples derived from chordoma patients treated at Massachusetts General Hospital, University of California, Los Angeles, and the University of Miami were included. Tumor specimens were sent for comprehensive molecular profiling using next-generation sequencing. The most frequently mutated genes were identified and categorized by subtype, and microsatellite instability and programmed death ligand-1 (PD-L1) staining were assessed. Histologic subtypes included 70 conventional (81.4%), nine chondroid (10.5%), and seven dedifferentiated chordomas (8.1%). The most common mutations were cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) (28 of 86, 33%), low-density lipoprotein receptor-related protein 1B (10 of 86, 12%), polybromo-1 (9 of 86, 11%), and epidermal growth factor receptor (EGFR) (8 of 86, 9%). By subtype, CDKN2A/B mutation was most common in conventional chordoma (24 of 70, 34%), and chondroid chordoma (3 of 9, 33%). CDKN2A/B and EGFR mutations were most common in dedifferentiated chordoma (2/7, 29%). Microsatellite instability was not detected in seven of 69 (10.1%) samples. PD-L1 staining of tumor and immune cells was scarce, with scores <1 in 38 of 41 (92.7%) and 22 of 25 (88%) patients, respectively. This study provides a robust, high-dimensional sequencing assessment from 86 chordoma tissue samples and a descriptive overview of the genomic landscape of this rare, difficult to treat malignancy. Future studies should include in vitro assessment of gain and loss of function of frequently altered pathways to validate these findings.

Chordomas are rare, aggressive tumors of the axial skeleton with limited treatment options. Genetic alterations in SMARCB1, a tumor suppressor gene, have been implicated in poorly differentiated chordomas, but their role in typical and chondroid subtypes remains unclear. This study examined 42 chordoma samples (26 typical, 16 chondroid) for SMARCB1 genetic alterations, expression patterns, and associated pathways. SMARCB1 knockdown experiments were conducted in chordoma cell lines, followed by comprehensive transcriptome analysis. No exonic SMARCB1 mutations were identified, but heterozygous loss was observed in 3/26 typical chordomas. SMARCB1 expression positively correlated with patient survival and epithelial-mesenchymal markers. Functional studies revealed that SMARCB1 knockdown significantly enhanced cell proliferation, migration, and invasion. Transcriptome analysis demonstrated enrichment of MYC targets, E2F targets, and cell cycle pathways in SMARCB1-low samples, while cellular adhesion pathways were downregulated. Notably, SLPI, LBH, and LOXL2 were significantly downregulated in SMARCB1-low samples. SMARCB1 plays an important role in chordoma progression, influencing prognosis and cellular behavior, despite infrequent genetic alterations. Its effects on key oncogenic pathways and cellular plasticity suggest potential for targeted therapies. These findings provide new insights into chordoma biology and lay the groundwork for developing SMARCB1-based prognostic tools and personalized treatment strategies.

Chordomas arise from remnants of the notochord. The aim of this study is to report a series of cases with operated skull base chordomas, with reviewing clinical data, assessing surgical strategy and outcome. We performed a 13-year retrospective study, between 2009 and 2022, in which we included patients operated for skull base chordomas. There were 6 males and 9 women, mean age 52.8 ± 16.55 years. Tumor site was clivus (13 patients), left cavernous sinus (one case) and sphenoidal sinus (one case). We performed endoscopic endonasal approach (18 times), transcranial subtemporal approach and combined approach. We achieved GTR in 8 patients, NTR in 4 patients, STR in 7 patients and biopsy in 1 patient. Grade of resection was associated with recurrence incidence (p=0.002).Histological exam revealed conventional chordoma in 14 cases, chondroid chordoma in 5 cases and dedifferentiated (chondrosarcoma) in 1 case. Patients' neurological status improved following surgery (p=0.000). Five patients underwent adjuvant conventional radiotherapy.Five patients presented local recurrence. All recurrences were reoperated using endoscopic endonasal approach. Survival analysis identified grade of resection and adjuvant radiotherapy as predictive factors for recurrence-free survival. Surgery is the treatment of choice in skull base chordomas. Surgical approach should be tailored according to tumor original site and extensions. Midline chordomas are proper candidates for endoscopic endonasal approach, while lateral lesions require transcranial surgery. Combined approaches should be used in extensive tumors. GTR and radiotherapy prolong recurrence-free survival. Further studies on larger samples of patients are needed.

Sacrococcygeal chordoma is a rare, locally aggressive malignant tumor originating from remnants of the notochord, and it represents the most common primary malignancy of the sacrum. This review provides an in-depth discussion of the clinical presentation, pathological features, imaging characteristics, and management of sacrococcygeal chordomas. These tumors typically present with local pain, neurological deficits, and a palpable mass, and they are known for their high recurrence rate and challenging surgical management. Imaging, especially MRI, is crucial for accurate diagnosis and surgical planning, given its ability to delineate the extent of the tumor and its relationship with surrounding structures. Complete surgical excision remains the cornerstone of treatment, with prognosis largely depending on the ability to achieve negative surgical margins. We present a case of a 45-year-old male who presented with bowel and bladder dysfunction and a painful, progressively enlarging mass over the sacrum. MRI revealed a large, well-defined soft tissue mass involving the distal sacrum and coccyx, extending into the retrorectal space. The patient underwent successful en bloc surgical resection, and histopathological examination confirmed the diagnosis of chondroid chordoma.

Distinct lesions are derived from notochordal cells (NCDL), ranging from benign to malignant ones. This study presents fifty NCDL cases diagnosed in a tertiary hospital of reference from the past 55 years: forty-two conventional chordomas, including one chondroid chordoma subtype, four benign notochordal cell tumors (BNCT), two conventional chordomas with BNCT foci, and two dedifferentiated chordomas. All patients were adults. Three BNCT were incidentally diagnosed, and one case presented local pain. Chordomas began with local pain and/or neurological symptoms. BNCT were well-defined intraosseous lesions, hypointense on T1-weighted images (WI) and hyperintense on T2-WI, without enhancement in the contrast. Conventional chordomas, including its chondroid subtype, were lobulated masses with cortical disruption and soft tissue extension, hypointense on T1-WI and hyperintense on T2-WI, with variable contrast enhancement. BNCT were histologically composed of solid sheets of vacuolated cells with clear cytoplasm and round and central nuclei. No atypia, lobular growth pattern, myxoid matrix, or bone infiltration were seen. Conventional chordomas were histologically composed of physaliphorous cells in a myxoid stroma with lobulated and infiltrating growth patterns. Observational follow-up using radiological controls was decided on for the BNCT cases. None of these cases presented local recurrence or metastasis. En-bloc resection and adjuvant radiotherapy were selected for sacral and vertebral chordoma cases. Sixteen patients died due to tumor-related factors; twenty-eight presented local recurrence, and four developed distant metastases. New therapeutic options are being studied for chordoma cases. Clinical, radiological, and histopathological data are necessary to properly diagnose and follow up of NCDL.

BackgroundChordomas are rare, malignant tumors typically centered in midline structures such as the clivus and sacrum, with peak prevalence in the fourth decade. Clival chordomas may secondarily extend to involve the nasopharynx and nasal cavity; however, primary extra-osseous chordomas are even more uncommon. We present an unusual case of a primary sinonasal chondroid chordoma arising from the maxillary sinus in a 5-year-old child. This is the second case of primary sinonasal chordoma reported in the literature so far, after Tao ZZ et al. and the first case of the chondroid variant.Case presentationA 5-year-old male presented with right-sided nasal obstruction, nasal congestion, and snoring for 2 months. Physical examination showed a reddish polypoidal mass in the right nasal cavity obstructing the choana with nasal septal deviation toward left side. Radiological examination with CT confirmed the presence of a well-defined, heterogeneously hyperdense lobulated mass in right maxillary sinus extending into right nasal cavity with intralesional coarse calcifications. MRI revealed expansile solid altered signal intensity mass, which appears to be isointense on T1-weighted imaging (T1WI) and heterogeneously hyperintense on T2-weighted imaging (T2WI) with a heterogeneous honeycomb pattern of enhancement. Differentials considered were rhabdomyosarcoma, nasopharyngeal carcinoma, and neuroblastoma metastasis. However, the lesion was pathologically proven as a chondroid chordoma. No association with skull base or clival lesion was found on review.ConclusionsPrimary sinonasal chordomas are rare in occurrence but should be considered a differential for sinonasal masses in the presence of characteristic MRI features, despite their uncommon location.

The aim of this study was to provide a quantitative synthesis of the survival outcomes for patients with skull base chordomas, focusing on the role of 1) the extent of resection (gross-total [GTR] vs non-GTR), 2) the type of surgery (primary vs revision), 3) tumor histology, and 4) the different use of adjuvant therapies (proton beam radiotherapy [PBRT], photon radiotherapy [RT], or none). A systematic review with a meta-analysis was conducted following the 2020 PRISMA guidelines. Observational studies describing adult and pediatric patient cohorts harboring skull base chordomas were included. The primary outcome measures were represented by the 5-year overall survival (OS) and progression-free survival (PFS) rates. The main intervention effects were represented by the extent of resection (GTR vs non-GTR), type of surgical excision (primary vs revision surgeries), tumor histology, and the different use of adjuvant therapies (PBRT, RT, or none). The pooled estimates were calculated using random forest models. The risk of bias was evaluated using the Joanna Briggs Institute checklist for case series. Six hundred forty-four studies were identified through a database and register search. After study selection, 51 studies and 3871 patients were included in the meta-analysis. The overall 5-year OS rate was 73%, which increased to 84% among patients undergoing GTR. The overall 5-year PFS rate was 52%, increasing to 74% for patients receiving GTR. The 5-year OS and PFS rates for patients undergoing PBRT were 86% and 71%, compared with 71% and 54% for patients receiving RT, and 55% and 25% when no adjuvant treatments were used. Patients undergoing their first surgery had 2.13-fold greater chances of being disease-free and 1.4-fold greater chances of being alive at 5 years follow-up compared with patients who received a revision surgery. Patients harboring chondroid chordomas had 1.13- and 1.9-fold greater chances of being alive at 5 years compared with patients with conventional and de-differentiated chordomas, respectively. The overall risk of bias was low in the included studies. The results of this comprehensive meta-analysis highlight the tremendous impact of GTR and adjuvant PBRT on improving OS and PFS of patients harboring skull base chordomas, with better survival rates demonstrated for patients with chondroid tumors. Even in experienced hands, the rate of surgical morbidity remains high. Proper management in high-volume centers is mandatory to reach the expected resection goal at the first surgical attempt and to reduce surgical morbidity. The introduction of the endoscopic endonasal approach was related to improved surgical and functional outcomes.

PurposeChordomas are rare malignant tumors that occur primarily in the axial skeleton. We seek to analyze trends affecting five-year overall survival (5y OS) among patients with primary spinal chordomas (PSC) of the vertebrae and sacrum/pelvis.MethodsThe Surveillance, Epidemiology, and End Results (SEER) Program was used to identify patients with PSC (ICD-O-3 histology codes 9370/3, 9371/3, and 9372/3) of the spine or sacrum/pelvis. Multivariate and univariate survival analyses were conducted to assess demographic, disease, or treatment characteristic trends.ResultsEight-hundred-ninety-six patients diagnosed with PSC were identified. Patients 0–54 years at diagnosis had improved 5y OS compared to those either 55–69 years (HR = 1.78; p = 0.046) or those between 70 and 85 + years (HR = 3.92; p < 0.001). Histology impacted 5y OS: Cox regression demonstrated variance among the three histologies assessed (p < 0.001), while univariate analysis demonstrated patients with dedifferentiated chordoma (1.0% of cohort; 33.3% [1.9,64.7]) and chondroid chordoma (2.0% of cohort; 52.5% [26.1,78.9]) had decreased 5y OS compared to those with general chordoma (72.2% [68.8,75.6]; p < 0.001). Nonmarried patients had decreased 5y OS on univariate analysis (65.2% [59.4,71.0] versus 76.2% [72.0,80.4]), with widowed patients being the primary driver of this on subanalysis. Treatment with gross total resection was associated with increased 5y OS (HR = 0.22, p < 0.001), as was treatment with radiotherapy (HR = 0.69, p = 0.030).ConclusionPatient age and marital status were significant demographic factors associated with changes in 5y OS among those with PSC. PSC histology is a potentially important prognostic factor in the management of disease.

We present the case of a 23-year-old man with a chondroid chordoma of the sternum. The patient underwent chest wall resection, followed by stabilization using a sandwich graft of Prolene mesh and methylmethacrylate, covered with bilateral pedicled musculus pectoralis flaps. After adjuvant radiotherapy and 2 years of follow-up, the patient developed a graft-associated infection. We removed the allogeneic material and the encapsulated abscess, and the wound was conditioned through negative wound pressure therapy. This time, wound closure and chest wall stabilization were achieved with a Prolene mesh covered by a free anterolateral thigh flap. This case demonstrates the importance of carefully considering the material for chest wall stabilization and establishing multidisciplinary cooperation.

Toxicity Outcomes of Hypofractionated Image Guided Pencil Beam Scanning Proton Beam Therapy for Spinal Chordomas

Objective: To investigate the clinicopathological features, diagnosis and differential diagnosis of notochordal tumors. Methods: The clinical, radiologic and pathologic data of 48 notochordal tumors were collected from 2008 to 2019 at Shanghai Jiaotong University Sixth People's Hospital. Expression of cytokertin, S-100 protein, vimentin, brachyury and INI1 was detected by immunohistochemistry. The pathologic differential diagnoses and biologic behavior of various types of notochordal tumors were analyzed using the new standard in the 5th edition of WHO tumor classification. Results: Four cases of benign notochordal cell tumor were confined to vertebral body. Histopathologically, they lacked lobular architecture and extracellular myxoid matrix. The tumor cells were vacuolated and had centrally or peripherally located round to oval nuclei, with small nucleoli, without atypia, mimicking mature adipocytes. No mitotic figures were seen. Two cases of poorly differentiated chordoma, from patients aged 12 years and 21 years respectively, were located in cervical vertebra, and were composed of cohesive sheets or nests of epithelioid cells, with focal rhabdoid morphology. There was relatively abundant eosinophilic cytoplasm and scattered cytoplasmic vacuoles. The moderately pleomorphic nuclei were round to ovoid with vesicular chromatin and mitotic figures could be seen. Extracellular myxoid stroma was observed focally. Forty cases of conventional chordoma and two cases of extra-axis chordoma had similar histologic features. All 48 cases expressed cytokeretin, 45 cases expressed brachyury, and two poorly differentiated tumors showed loss of INI1/SMARCB1. Conclusions: There are four subtypes of chordomas: conventional, dedifferentiated, poorly differentiated and extra-axis. Chondroid chordoma is no longer thought to be a distinct entity. Each type has its unique clinicopathological characteristics. Brachyury is highly specific and sensitive for the diagnosis of various notochordal tumors. Poorly differentiated chordoma shows distinct clinicopathological features, including young age and loss of immunohistochemical expression of INI1/SMARCB1, and its diagnosis requires the combined detection of brachyury and INI1/SMARCB1.

ABSTRACTContext:Skull base tumors are varied in children and are particularly challenging to pediatric neurosurgeons, with few papers in the literature describing the evolution, complications, and outcome. The authors evaluated long-term outcomes in children submitted to skull base tumor surgery and performed a literature review.Aims:The aim of this study was to analyze surgical results, complications, and outcomes, on comparison with previous publications.Materials and Methods:A retrospective analysis of children undergoing surgery at a single institution between 2000 and 2018 for lesions of the cranial base was carried out. In addition, a literature review was carried out describing a total of 115 children operated on for skull base tumors.Statistical Analysis:Chi-squared and Fisher’s exact tests were performed to compare the distribution of categorical variables and a nonparametric Mann–Whitney U test was used to perform intergroup comparisons of continuous variables.Results:Seventeen children ranging in age from 8 months to 17 years (mean, 10.9 years) underwent skull base approaches. Tumor types included schwannoma, meningioma, chondroid chordoma, mature teratoma, epidermoid cyst, hemangiopericytoma, rhabdomyosarcoma, myofibroblastic inflammatory tumor, fibromyxoid sarcoma, Crooke’s cell adenoma, ossifying fibroma, osteoblastoma, nasopharyngeal angiofibroma and Ewing’s sarcoma. Gross total resection was achieved in 6 patients (35.3%), 12 patients (70.6%) had benign histology, and 5 patients (29.4%) had a malignant tumor. Transient postoperative cerebrospinal fluid leak affected only one patient. Thirteen children (76.4%) had a residual neurological deficit at last follow-up evaluation. Three (17.6%) surviving patients received adjuvant therapy. The rate of recurrence or lesion progression was 17.6%.Conclusions:Skull base tumors in children present a therapeutic challenge because of their unique pathological composition and can lead to considerable morbidity and mortality in pediatric age.

Chordomas are rare, slowly growing, locally aggressive neoplasms of bone that arise from embryonicremnants of the notochord. Chondroid-chordoma is an uncommon variant of chordoma. These tumorstypically occur in the axial skeleton. Here we report a rare occurrence of chondroid variant of chordomaat sacrococcygeal region in a 60 year old female. Magnetic resonance imaging revealed expansile massinvolvingsacrococcygeal region.Gross and microscopic examination confirmed chondroid chordoma.Laterpatient underwent radiotherapy, doingwell,on a one year follow up. Chondroid chordoma is discussed dueto its predilection for occurrence at sacrococcygealregion and its more favorable prognosis compared withthat of conventional chordoma.

Chordoma is a malignant tumour showing notochordal differentiation with three identified subtypes including chordoma not otherwise specified, chondroid chordoma and dedifferentiated chordoma. Dedifferentiated chordoma is rare and carries the worst prognosis of all subtypes due to rapid progression and potential for metastases. It is characterized by a high-grade sarcomatous component juxtaposed to conventional chordoma. We report a case of a dedifferentiated chordoma in a 71 year old woman who presented with pain in the lower back, numbness of feet and loss of weight of recent onset. Per-rectal examination revealed a soft tissue mass in the presacral region while imaging showed a solid and cystic lesion with calcifications in the presacral region. The radiological impression was of a retro rectal cystic hamartoma, an epidermoid cyst, or a chronic abscess. The resected specimen comprised a lobulated mass of soft, gelatinous tissue with haemorrhage and necrosis. Microscopy showed a biphasic tumour composed of conventional chordoma juxtaposed with high-grade sarcomatous component. Morphology and immunohistochemistry were compatible with a chordoma with a focal high-grade spindle cell sarcomatous component in keeping with a dedifferentiated chordoma.

Chordomas are rare, malignant and locally aggressive tumors that are derived from the remnants of primitive notochord, out of which chondroid chordomas are even rarer. Very few case reports have described this variant, which is difficult to pick up on cytopathology alone and has a number of other differentials too. We report here a case of chondroid chordoma at the sacrococcygeal region that was diagnosed on FNAC in an elderly male patient emphasizing on its cytomorphology and how to differentiate from its cytological mimickers.

IntroductionChordoma is a malignant tumor predominantly involving the skull base and vertebral column. This study aimed to investigate the molecular characteristics of PTEN and CDKN2A in conventional and chondroid chordomas and their correlation with clinical prognosis.Materials and MethodsA total of 42 patients were enrolled, including 26 patients with conventional chordoma and 16 patients with chondroid chordoma. Clinicopathological profiles and tissue specimens were collected. Gene sequencing and fluorescence in situ hybridization were performed to identify genetic alterations in the PTEN and CDKN2A genes. Immunohistochemical staining was used for semiquantitative evaluation of PTEN and CDKN2A expression.ResultsGene sequencing revealed an intron SNP (c.80–96A>G) and a missense mutation (c.10G>A; p.Gly4Arg) in the PTEN gene and a missense mutation (c.442G>A; p.Ala148Thr) in the CDKN2A gene. Loss of the PTEN locus was identified in 25 (59.5%) cases, and loss of the CDKN2A locus was found in 28 (66.7%) cases. There was no significant correlation between progression-free survival (PFS)/overall survival (OS) and loss of PTEN or CDKN2A. The patients with lower PTEN expression showed significantly shorter PFS and OS than those with higher expression, while there was no significant difference in PFS or OS between patients with lower CDKN2A expression and those with higher CDKN2A expression.ConclusionOur findings delineated the genetic landscape and expression of PTEN and CDKN2A in chordomas. PTEN expression may serve as a prognostic and predictive biomarker for chordomas.

Introduction:Chordoma is a rare sarcoma of the axial skeleton. The incidence of this tumor is different between races. To understand the epidemiologic characteristic and due to rarity of this pathology, large number of cases should be evaluated through national data registries.Materials and Methods:All pathologically confirmed cases of chordoma were derived from the Iran National Cancer Registry. Descriptive analysis was performed to extract age-standardized and age-specific incidence rates. Data regarding tumor location and chordoma subtypes were derived and analyzed.Results:One hundred twenty-two cases of chordoma including 80 male and 42 female were identified. One hundred seven cases of nonotherwise specified chordoma, 14 chondroid chordoma, and one dedifferentiated chordoma were detected. The age-standardized incidence rate (ASIR) of chordoma was 0.28. Chordoma of the sacrum composed 67.2% of cases. The mean survival time was 4.5 years.Conclusion:Epidemiology characteristic of chordoma in Iran is similar to other studies; however, the total ASIR was lower and the incidence in sacrum is nearly twice respect to the mobile spine. While men affected by sacral chordoma in relatively older age, the female patients had higher mean age in case of mobile spine involvement. The survival rate of chordoma is significantly lower in comparison with other studies.

Objective To investigate the pathological characteristics and changing trend in primary and local recurrent skull base chordoma, and to analyze their correlation with the outcomes. Methods A total of 89 samples of primary and local recurrent tumors pathologically confirmed from 38 patients who were treated in Neurosurgery Department of Beijing Tiantan Hospital, Capital Medical University between February 2005 and December 2014 were retrospectively enrolled into this self-control study. After HE staining, the pathological features such as nuclear atypia, mitosis, matrix ratio, necrosis, bone invasion and pathological subtypes were analyzed. The expressions of p53, Ki-67, EGFR, VEGFR and TRAF6 were detected by immunohistochemical staining. The changes of pathological indexes as above in primary and recurrence stages were compared. Cox analyses were used to analyze the effects of above pathological indexes on the progression-free survival (PFS) of patients with primary tumor, and the effects of the changes regarding those factors on the overall survival (OS). Results Ten cases (35.7%) of classical subtype changed to myeloid subtype, while none of chondroid chordoma changed to myeloid subtype after recurrence. Twelve cases (31.6%) demonstrated necrosis companied with tumor recurrence. Twenty-five cases (73.5%) of primary tumor showed high-expression of TRAF6, and 19 cases (50.0%) had decreased expression intensity of TRAF6 after tumor recurrence. There were 16 cases (42.1%) and 15 cases (39.5%) with upregulation of P53 and EGFR respectively. Necrosis (HR=7.1, 95% CI: 1.4-37.1, P=0.006), pathological subtype (HR=3.9, 95% CI: 1.2-7.2, P=0.040) and TRAF6≥3 grade (HR=0.2, 95% CI: 0.1-0.5, P<0.001) in primary tumors were directly related to PFS, and TRAF6≥3 grade (HR=0.2, 95% CI: 0.1-0.5, P<0.010) was an independent protective factor for PFS. There was no significant difference in the OS rate among the above pathological changes. Conclusions Classical chordoma shows malignant transformation to the myeloid subtype, which is not found in chondroid subtype. The expression of TRAF6 decreases gradually with tumor recurrence, and its high expression in primary tumor is an independent protective factor for PFS. Key words: Chordoma; Skull base neoplasms; Pathology; TNF receptor-associated factor 6; Prognosis

Introduction:Tumors are the second-most common cause of death after cardiovascular diseases. Due to the high prevalence and mortality rate, brain tumors are of great importance and makeup about 5% of all tumors. Different types of brain tumors have their special pattern based on age, sex, complaints on admission, radiological signs and sometimes, their family history and seem these patterns are changing according to the geographic region over time. In this study, we evaluate the incidence of brain tumors in the northwest of Iran.Materials and Methods:All patients with brain tumor diagnosis that were hospitalized between April 2011 and March 2016 evaluated. Exclusion criteria were considered as secondary tumors of the central nervous system (CNS) (metastases) and duplicate records for the recurrent disease of the same patient. Data collected from their documents and analyzed with SPSS version 16.Results:In the present study, male to female (M: F) ratio is 1:1. 92.5% of tumors are primary in which meningiomas (22%) and glioblastoma multiforme (GBM) (19.6%) are the most common types. The rarest tumor types are neurocytoma (0.3%) and chondroid chordoma (0.3%). GBM is the most common tumor in the male population and meningiomas are most common in females. Medulloblastoma and meningioma with a median age of 11 and 58 years, respectively, were known as the most common primary CNS malignancy of the youngest and oldest age of study group.Conclusion:The obtained data from this study revealed that age and sex are associated with the tumor types, which is consistent with the previous results. Brain tumors involvement pattern is changing in male patients somehow there is a tendency of involving more aggressive and malignant tumor types in male individuals could be seen.