Diagnostic Challenges of Gliosarcoma: Case report of a Rare Glioblastoma Histopathological Variant

Sergey Karasev¹Rustam Talybov^2,3*Shamil Chertoyev³Tatyana Trofimova⁴Vadim Mochalov³Tatyana Kleshchevnikova³Natalya Loginova⁵Irina Karaseva³

• ¹Department of Neurosurgery Federal Center of Neurosurgery, Tyumen, Russia
• ²Tyumen State Medical University, Tyumen, Russia
• ³GBUZ Oblastnaa kliniceskaa bol'nica No 2, Tyumen, Russia
• ⁴Pervyj Sankt-Peterburgskij gosudarstvennyj medicinskij universitet imeni akademika I P Pavlova, Saint Petersburg, Russia
• ⁵Tyumen State Medical University , Tyumen , Russia, Tyumen, Russia

Background: According to the 5th revision of World Health Organization (WHO) of Central Nervous System (CNS) tumors classification, gliosarcoma is a malignant tumor grade 4 and is the rarest and aggressive subtype of IDH-wild type glioblastoma. The special histopathological feature of the tumor is its biphasic differentiation including both the glial and sarcomatous (mesenchymal) components in the tumor. The characteristics mentioned above create difficulties in radiological and histological diagnosis. Due to its rarity, gliosarcoma is typically not even considered in the differential diagnosis. Case Presentation: A 55-year-old man exhibiting acute right-sided hemiparesis and disorientation for 12 hours with loss of consciousness is described in this clinical case study. Brain МRI revealed intracerebral mass in the left fronto-parietal area with the close relationship to the dura mater, ring-like enhancement, severe perifocal edema, restricted diffusion of the solid component, internal vascular shunts, microhemorrhages and had elevated perfusion values. At the preoperative stage the differential diagnosis included glioblastoma, solitary metastasis and possibility of an anaplastic meningioma. The tumor microsurgical resection was performed. According to the results of histological and immunohistochemical studies gliosarcoma was diagnosed. Discussion: The only characteristic gliosarcoma feature was the phenomenon of solid node heterogeneity detected on conventional T2 weighted sequence: the combination of hypo-and hyperintense parts. While mpMRI aids in differentiating high-grade gliomas, metastases, and meningiomas, gliosarcoma remains underrecognized due to overlapping features. The observed T2 heterogeneity may serve as a potential radiological marker for gliosarcoma. The accurate and timely identification of brain tumor type is required to establish the appropriate extent of resection in surgical planning. Conclusion: The case publication intends not to ignore the data of conventional sequences and consider them to be included in the structure of multiparametric MRI protocol. However, larger studies are needed to validate these findings and refine diagnostic criteria for this rare tumor.