A 74-year-old woman with no personal history of interest consulted our Center for a progressive picture of six months of dizziness without sensation of spinning objects, accompanied by nausea, occasional vomiting and gait instability.
The patient also reported tinnitus in the left ear.
During the physical examination a mass was found in the left retroauricular region, painless to palpation, firm consistency and attached to the skin.
No lymphadenopathies were detected.
Neurological examination revealed only mild gait instability without any other associated focality.
Cranial computed tomography (CT) showed a large, extraaxial, lobulated, hyperdense, non-calcified lesion, with little perilesional edema, located in the left half of the cranioid fossa.
The tumor showed heterogeneous contrast uptake.
Cranial magnetic resonance imaging (MRI) showed that the lesion, of dimensions fixed at 7.6×3.5×3.5 cm, was closely related to the tentorium, compressing the left ventricle fourth lobe and cerebellum.
It was an isointense lesion on T1-weighted images and hyperintense on T2-weighted images with respect to the cerebral cortex, which showed intense enhancement after gadolinium administration.
Signs of intralesional serpinginous vacuum were also observed, probably related to tumor vessels.
Arteriography showed a highly vascularized mass only from branches of the left external carotid artery, through the occipital, posterior auricular arteries and branches of the ascending pharyngeal artery.
The left transverse-sigmoid sinus was permeable although with lower flow than its contralateral counterpart.
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Medianing a left retromastoid approach, an extraaxial lesion with hemorrhagic characteristics was macroscopically resected, which was located on the tenthmuscle of the occipito-temporal convexity.
The left transverse sinus was resected and the tenthrium was dissected.
The procedure was completed with bone reaming of callus and reconstruction of the surgical defect with dural plasty, autologous abdominal fat and fibrin of biological origin (Sympson grade I resection).
Immediate postoperative MRI confirmed complete resection of the lesion.
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The histological study showed that it was a hemangiopericytoma when a hypercellular lesion was observed, consisting of cells with low cytoplasm and elongated nuclei.
A dense pericellular mesh was drawn when reticulin was applied.
Immunohistochemical techniques were definitive showing positive vimentin markers and negative epithelial membrane antigen (EMA).
Proliferative index was 5-10%.
The patient recovered satisfactorily and underwent adjuvant radiotherapy to complete the treatment of the lesion which ended three months later, receiving a total dose of 60 Gy.
Sixteen months after surgery there is no clinical evidence of local recurrence or distant metastases.
