Sellar recurrent hemangiopericytoma without metastasis : a case report

Primitive hemangiopericytomas of the central nervous system are rare and represent less than 1% of intracranial tumors. Their nonspecific clinical and imaging can be misleading and bring to a mistaken diagnosis of meningioma. Radical surgery is the treatment of choice, but must be supplemented with postoperative radiotherapy. Hemangiopericytomas have a high potential for recurrence and metastasis. Sellar location is very rare and can simulate a pituitary adenoma.We report a case of a 24 year-old woman diagnosed with sellar recurrent HPC without metastasis. Pan African Medical Journal. 2016; 23:179 doi:10.11604/pamj.2016.23.179.7162 This article is available online at: http://www.panafrican-med-journal.com/content/article/23/179/full/ © Doléagbénou Agbéko Komlan et al. The Pan African Medical Journal ISSN 1937-8688. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Pan African Medical Journal – ISSN: 19378688 (www.panafrican-med-journal.com) Published in partnership with the African Field Epidemiology Network (AFENET). (www.afenet.net) Case report Open Access


Introduction
Hemangiopericytoma (HPC) is a potentially malignant tumor originating from Zimmermann's pericytes around capillaries and postcapillary venules [1].HPCs are located most often, in the musculoskeletal system and the skin [2].Intracranial HPCs are uncommon tumors, accounting for less than 1% of primary central nervous system (CNS) tumors, and constitute 2% to 4% of meningeal tumors [3].HPC occurred generally on supratentorial with most frequency in parasagittal and falcine region mimicking meningioma [1].These tumors have a high potential of recurrence and metastasis [4].We report a case of a recurrent sellar HPC without metastasis.

Patient and observation
A 24-year-old woman was admitted with a 1-month history of headache, and bilateral visual loss.Physicalexamination found no neurological deficit, her visual field was 1/10, and bitemporal hemianopsia.The other cranial nerves were normal.She had no medical pasthistory of hypertension, diabetes mellitus or pulmonary tuberculosis.Brain CT scan showed a sellar and supra sellar lesion intensely and homogenouslyenhanced by contrast-agent.Brain magnetic resonance images (MRI) revealed an intrasellar and suprasellar mass with the compression of the chiasm.The lesion was isosignal on T1-weighted sequence and slightly hyperintense on T2wheighted sequence, with an intense and homogenous enhancement (Figure 1 (A).Endocrinological studies showed hypopituitarism.The possible diagnosis included pituitary adenoma and meningioma.Patient underwent surgery usingtranssphenoidal approach.The tumor appears highly vascularized accommodated a subtotal resection (Figure 1 (B).Histologicaldiagnosis was hemangiopericytoma (Figure 2).She received a local radiotherapy (52 Gy) of the pituitary fossa.Two years later, she complained of headaches and visual loss.Brain MRI showed a contrast-enhancing soft tissue mass arising from the pituitary fossa (Figure 3).Partial resection of the tumor was done and pathologic findings were compatible with hemangiopericytoma.Thoracoabdominal CT scanwas normal.The patient received a second radiotherapy with favorable outcome after one year follow-up, without recurrence of the tumor (Figure 4).

Discussion
Intracranial HPCs are uncommon tumors, accounting for less than 1% of primary CNS tumors, and constitute 2-4% of meningeal tumors [3].They were previously classified as angioblastic sub-type meningiomas [5].Since 1993, HPCs are classified in the group of "mesenchymal, non-meningothelial tumors" [6].These tumors arise from smooth muscle perivascular pericytes of Zimmerman.They are more aggressive than meningiomas, with high frequency of recurrence and metastasis [4].HPCs are commonly located insupratentorial region (parasagittal or falcine) [1].Sellar location is very rare.Few cases have been reported in the literature [1,4,7].It occurs on male patients in 55% to 77% from 38 to 42 years [1].In our case the patient was a young woman of24 years old.
Brain imaging (CT and MRI) are important but couldn't make a difference with meningioma [7][8][9].However, some elements could help to make a difference between HPC and meningioma.Intratumoral calcification or hyperostosis reaction in contact with the insertion zone are never viewed in HPCs; bone destruction without piping osteosclerosis is a classic look, but nonspecific.The edges are often irregular and polylobed.Contrast enhancement after injection is often intense and heterogeneous [7,8].In sellar locations, diagnostic of pituitary macroadenoma is most often carried, and transsphenoïdal approach is proposed.The treatment of primitive HPCscentral nervous system based on complete resection of the tumor, followed by radiation in order to prevent recurrence and metastasis [8][9][10].Immunohistochemistry can differentiate HPC from meningioma: HPC stains positive for CD 34, factor VIII, and vimentin but negative for S-100 and epithelial membrane antigen (EMA) [3,11].
HPCs can recur locally or distantly in the neural axis or metastasize to extraneural sites [12].Schiariti reported 28 cases of local recurrence, in a series of 39 patients.The recurrence rate at 1, 5, and 15 years was 3.5%, 46%, and 92%, respectively.Extraneural metastasis occurred in 8 patients (26%) at an average of 123 months after initial surgery [12].In our case the recurrence appears after two years.According to Myung-Hwan [1], it is after 9 years.Recurrence is a late event in the natural history of HPC.Close follow-up for a long period after the first surgery is needed.Complete excision favorably affects recurrence and survival, as opposed to incomplete excision [13].Because the hypervascular characteristics of HPC simply "radiosensitivity", postoperative adjuvant radiotherapy appears to significantly decrease the local recurrence rate and lengthen recurrence-free duration.However recurrence remains a common treatment outcome regardless of initial strategy [13].Stereotactic radiosurgery is benefic in case of recurrent HPCs [14].Extended analysis using lesion data available revealed that higher marginal dose (≥ 17 Gy) was also significant (P = 0.028).Kim and al., reported that Gamma Knife Stereostatic Radiosurgery provides an effective and safe adjuvant management option for patients with recurrent or residual HPCs [14].The local tumor recurrence in our case could be assigned to incomplete excision at the first operation.

Conclusion
Sellar and suprasellar HPC can mimic a pituitary tumor.This case illustrates a difficulty to establish diagnostic on imaging and clinical exams.Diagnosis is made byhistological studies.Unfortunately HCP has usually poor prognosis.Although rare in sellar location, HCP should be considered in differential diagnosis of pituitary tumors.

FiguresFigure 1 :
Figures Figure 1:(A): Preoperative magnetic resonance image showing a sellar and suprasellar solid mass; (B): postoperative magnetic resonance image showing a remnant Figure 2: Histology of tumor, immunohistochemical staining revealing positive reaction for CD 34 Figure 3: Recurrent tumor arising from the pituitary fossa Figure 4: MRI one year after second surgery and radiotherapy

Figure 3 : 4 :Figure 1 :
Figure 1: (A): Preoperative magnetic resonance image showing a sellar and suprasellar solid mass; (B): postoperative magnetic resonance image showing a remnant Figure 2: Histology of tumor, immunohistochemical staining revealing positive reaction for CD 34 Figure 3: Recurrent tumor arising from the pituitary fossa Figure 4: MRI one year after second surgery and radiotherapy

Figure 2 :
Figure 2: Histology of tumor, immunohistochemical staining revealing positive reaction for CD 34

Figure 3 :
Figure 3: Recurrent tumor arising from the pituitary fossa

Figure 4 :
Figure 4: MRI one year after second surgery and radiotherapy