Keywords
anaplastic oligodendroglioma - superior sagittal sinus
Palavras-chave
oligodendroglioma anaplásico - seio sagital superior
Introduction
Oligodendrogliomas represent the 3rd most common type of glial tumors, corresponding to between ∼ 4 and 15% of all gliomas of the central nervous system (CNS).[1]
Anaplastic oligodendrogliomas (AOs) (World Health Organization [WHO] grade III)[2] correspond to ∼ 23% of all oligodendrogliomas.[3] They correspond to a tumor with malignant histological characteristics, focal or diffuse, associated with a worse prognosis,[1] in comparison to the oligodendrogliomas WHO grade II.[2] Anaplastic oligodendrogliomas are associated with a 5- and 10-year average survival rate of 63% and 33%, respectively.[4]
In the present case report, we describe the case of an AO with a pattern of tumor dissemination not described in the literature, into the superior sagittal sinus (SSS), with its consequent obliteration, in a patient with no evidence of tumor recurrence elsewhere.
Case Report
A 30-year-old woman presented with an inaugural seizure in 2013. She was submitted to a computed tomography (CT) of the brain that revealed a right parietal corticosubcortical lesion, with calcifications ([Fig. 1]), and to a magnetic resonance imaging (MRI) of the brain that revealed a hypointense lesion in the T1 weights with areas of contrast enhancement ([Fig. 2]) suggesting a high-grade glioma. The patient underwent a surgical excision with gross total resection (GTR) of the lesion. In the postoperative period, she developed a left hemisphere apraxia and a left inferior quadrantanopsia.
Fig. 1 Computed tomography scan showing a right parietal lesion with calcification.
Fig. 2 Axial T1-weighted magnetic resonance imaging showing a hypointense right parietal lesion with areas of contrast enhancement.
The neuropathological study showed a highly cellular glial tumor, with diffuse invasion of the cerebral parenchyma, composed of cells of relatively uniform round nuclei and with frequent perinuclear halos ([Fig. 3]). Necrosis, frequent mitoses, and a moderate proliferation index were also observed. The immunohistochemistry study was positive for glial fibrillary acidic protein (GFAP), and the tumor was isocitrate dehydrogenase (IDH-1) and α thalassemia/mental retardation syndrome X-linked (ATRX) positive. Based on these characteristics, the diagnosis was AO (World Health Organization grade III[2]).
Fig. 3 Hematoxylin and eosin staining showing a hypercellular tumor with round nuclei with a perinuclear halo, with frequent mitoses.
The complementary treatment was started according to the Roger Stupp protocol. The patient completed 30 sessions of radiotherapy (2Gy/session, in a total of 60 Gy), with concomitant temozolomide 75mg/m2 for 7 days per week, for 6 weeks. After that, she underwent 6 cycles of adjuvant temozolomide 150mg/m2 for 5 days per month.
Four years after the initial diagnosis in an imaging control by MRI, a recurrence of the tumor was observed, located within the SSS in the middle and posterior third, with no recurrence elsewhere, particularly in the surgical site ([Fig. 4]). Considering the hypothesis of surgical reintervention, an angiography was performed, which confirmed the absence of blood flow in the invaded portion of the SSS ([Fig. 5]).
Fig. 4 Sagittal T1-weighted magnetic resonance imaging with contrast showing tumor recurrence located within the superior sagittal sinus in the middle and posterior third.
Fig. 5 Angiography with absence of flow in the middle and posterior third of the superior sagittal sinus.
The patient was submitted to a new surgical intervention with en bloc resection of the occluded SSS, and it was verified intraoperatively that the external walls of the sinus were not invaded by the tumor and had a cortical vein that drained to the occluded portion of the SSS ([Figs. 6] and [7]). A postoperative MRI was performed, which showed the total removal of the invaded portion of the sinus ([Fig. 8]). The neuropathological study showed a tumor with the same characteristics as the previous tumor, and the walls of the sinus were not invaded by the tumor ([Fig. 9]).
Fig. 6 Intraoperative images showing the sinus walls macroscopically without tumor invasion and a cortical drainage vein in the direction of the occluded superior sagittal sinus.
Fig. 7 En bloc resection of the tumor.
Fig. 8 Second surgery postoperative sagittal T1-weighted magnetic resonance imaging showing the resection of the occluded sinus.
Fig. 9 Hematoxylin and eosin staining showing a hypercellular tumor, but no invasion of the sinus wall by malignant cells.
Currently, the patient presents 5 years of global survival, with status 1 in the Eastern Cooperative Oncology Group (ECOG) Scale of Performance Status.
Discussion
Oncological diseases are often associated with hypercoagulable states due to the prothrombotic properties of neoplastic cells.[1] Malignant tumors of the CNS, mainly gliomas, are associated with deep venous thrombosis and pulmonary thromboembolism.[1]
[5] Several cases of venous sinus thrombosis associated with malignant CNS tumors and complementary treatments have been described in the literature.[6]
The case described in the present report refers to a tumor that spread to the interior of a cerebral venous sinus, without continuity spread, since the outer wall of the sinus was not invaded and there was no evidence of disease progression elsewhere, particularly in the surgical site. From the research done in the PubMed and Google Scholar databases, we have found no registered case of exclusive dissemination to the venous sinuses of a glial tumor.
We believe that because glial tumors are an oncology pathology, a state of hypercoagulability may have occurred, which in turn has caused a decrease in the SSS drainage flow. This fact created favorable conditions for the tumor cells to spread to the interior of the sinus through cortical veins and to find conditions to fix in and metastasize to the SSS.
Conclusion
Although no case is described in the literature, glial tumors can spread into the venous sinuses without further progression of the disease, as we have described in the present case.
In the case of absence of blood flow of the venous sinuses, in the context of CNS oncological pathology, we must always take into account in the differential diagnosis the possibility of obstruction caused by tumor invasion, especially in glial tumors.
