INTRODUCTION: Central nervous system (CNS) meningeal hemangiopericytoma (MHPC) is a rare entity accountingless than 0,5-1% of all CNS tumors. MHPC present a mesenchymal origin, arising from pericytes of the meningeal capillaries. There are classified as solitary fibrous tumors grade II-III (WHO CNS tumors classification 2016).
Although MHPC can arise along the entire CNS the supra tentorial location is more common in close relation with the meninges. MHPC are more often observed in youngpopulation, with an average age presentation around 30-50 y-o and witha slight male predisposition.
MATERIAL AND METHODS: A 61y-o male was admittedin our department with a personal history of anosmia and an anatomopathological report ofhemangiopericytoma based in a endoscopical endonasal biopsy performed in a different institution.
A CT and MRI showed an intense contrast enhancement lesion (4 x 5 x 4,5cm) center at the frontal sinus eroding its posterior table and with a bilateral expansion into both frontoethmoidal receesses. Besides, a multilobulated posterior extension toward both frontal lobes was observed.
24 hours before surgery endovascular procedure was performed aiming to reduce the tumoral vascular supply. A single-stage combined bicoronal-bifrontal assisted by endoscopical endonasal approach was performed. A gross-total resection was achieved. There were no intra- or postoperative complications and the patient was discharged in the 7 day post op. Histopathological examination confirmeda MHPC WHO grade II.
Following the recommendations of the Radiation Oncology department, hypofractionated adjuvant radiotherapywas provided to the patient (total dose: 54 Gy). The patient remains asymptomaticand no recurrence on 12 months follow-up.
DISCUSSION: MHPCs arevery unusual CNS tumors.
MHPC and angioblastic/anaplastic meningiomapresent clinical, pathological and imaging similarities. Because they receive different treatment and have different prognosis, it isessential to make a precisedifferential diagnosis. Inmuno-histochemical studies are crucial in that aim.
MHPC are distinguished due to their hypercellularity, higher mitotic index, and microscopic tendency to bulge into vascular lumens; additionally, they have a strong tendency to local recurrence and until 20% can metastasize, typically to liver, lung and bone.
Patients with a gross-total total resection and postoperative radiation have demonstrated the best prognosis.
CONCLUSIONS: A single-stage combined bicoronal-bifrontal assisted by endoscopical endonasal approach followed by hypofractionated adjuvant radiotherapy it is safe and effective strategy in the MHPC treatment. Further studies are necessary to confirm this observation
Image 1: MRI preop
Image 2: combined approach
Image 3: nasosptal flap over pericranial flap
Image 4: MRI postop