Indian Journal of Pathology and Microbiology
Home About us Instructions Submission Subscribe Advertise Contact e-Alerts Login 
Users Online: 19
Print this page  Email this page Bookmark this page Small font sizeDefault font sizeIncrease font size


 
HISTOPATHOLOGY SECTION - CASE REPORT Table of Contents   
Year : 2008  |  Volume : 51  |  Issue : 1  |  Page : 53-55
Angiomatous meningioma: A diagnostic dilemma


Department of Pathology, Sri Ramachandra Medical College and Research Institute, Porur, Chennai, Tamil Nadu, India

Click here for correspondence address and email
 

   Abstract 

Angiomatous meningioma accounts for 2.1% of all meningiomas. It has features of a typical benign meningioma with many small or large vascular channels which may predominate over its meningothelial elements. We present here a series of three cases of angiomatous meningioma, which posed diagnostic difficulty to clinicians, radiologists, and pathologists. All the three cases showed a tumor entirely composed of thin-walled vascular channels and cells with bland morphology in the background. The diagnosis was confirmed by immunohistochemistry. We present series of three cases to highlight the histomorphological features of this uncommon variant of meningioma that could help in distinguishing it from hemangioblastoma and hemangiopericytoma.

Keywords: Angiomatous meningioma, differential diagnosis, vascular

How to cite this article:
Rao S, Rajkumar A, Kuruvilla S. Angiomatous meningioma: A diagnostic dilemma. Indian J Pathol Microbiol 2008;51:53-5

How to cite this URL:
Rao S, Rajkumar A, Kuruvilla S. Angiomatous meningioma: A diagnostic dilemma. Indian J Pathol Microbiol [serial online] 2008 [cited 2014 Nov 28];51:53-5. Available from: http://www.ijpmonline.org/text.asp?2008/51/1/53/40397



   Introduction Top


Neoplasms of the meninges are derived from mesenchymal elements normally present at this site and the most common tumor is meningioma incidence of which is quoted to be 13 to 26% in different studies of primary central nervous system (CNS) tumors. However, other mesenchymal lesions may also occur in this region and may cause considerable diagnostic difficulties. Hemangiopericytoma was earlier considered to represent a variant of meningioma. It is the most common nonmeningothelial mesenchymal lesion. Melanocytic tumors and hemangioblastoma are other tumors which can also occur at this site. Most meningiomas are benign and belong to World Health Organization (WHO) grade I, but certain variants which have a less favorable outcome are categorized into WHO grades II and III. Angiomatous meningioma belongs to WHO grade I category and accounts for 2.1% of all meningiomas. [1],[2] It occurs in middle-aged persons and shows a female predilection similar to a typical meningioma.


   Case History Top


Salient clinical and radiological details are described in [Table - 1].

Each of the three cases underwent frontal craniotomy on the lesional side. Peroperatively, the tumor was highly vascular and was separated from the brain parenchyma, but attached to the dura. Dura was opened, reflected with complete surgical excision of tumor.

Frozen section and squash preparation showed a highly vascular tumor, but a conclusive opinion could not be arrived at.

Histopathological examination

The tissue fragments received were fixed in 10% buffered formalin and were processed routinely. Hematoxylin and eosin (H&E) stained sections showed highly vascular tumor consisting predominantly of dilated vascular spaces with intervening areas showing spindle to oval cells with abundant cytoplasm and oval vesicular nuclei [Figure - 1]. Some of these cells showed vacuolated and clear cytoplasm [Figure - 2]. Tumor did not show any endothelial proliferation or mitotic activity. Occasional calcified structures were also seen. Impression of a vascular lesion was made and the differential diagnoses included were angiomatous meningioma, hemangioblastoma, and hemangiopericytoma. However, the diagnosis of angiomatous meningioma was confirmed by immunohistochemistry. The tumor cells showed positivity for epithelial membrane antigen (EMA) [Figure - 2], cytokeratin, progesterone and negativity was obtained with CD34 [Figure - 1]. Mindbomb homolog 1 (Drosophila) [MIB-1] labeling index was <2% in both the tumors indicating WHO grade I.


   Discussion Top


Angiomatous meningioma is a rare subgroup of meningiomas in which numerous vascular channels prevail on the background of an otherwise typical meningioma. [1] Until now clinicopathologic characteristics of angiomatous meningioma have not been systematically analyzed and studied in detail except by Martin et al. [2] In their study, they found seizures and neurological deficit to be the common presenting symptoms though few patients presented with headache. In the present study, patients presented with headache but one patient also gave history of seizures, syncopal attack, and hemiparesis. Age and sex distribution of patients studied were similar to a typical meningioma.

Meningiomas show isointensity or hyperintensity to the cerebral cortex in magnetic resonance imaging (MRI). Short extension of contrast enhancing tissue along the dura (dura tail) is a valuable diagnostic feature. Radiographically, there is no other additional feature to help in subclassification of meningiomas, though angiomatous meningioma (in spite of belonging to WHO grade I) shows perilesional edema. Contrast enhancement is a feature seen in glioma, hemangioblastoma, and typical meningioma. Perilesional edema is usually seen in atypical meningioma but when seen in this variant it is not a sign of atypia or malignancy. [2],[3],[4] Tamiya et al . examined the radiological and histological features influencing the development of peritumoral brain edema analyzed 125 patients with primary intracranial meningiomas. They found that meningiomas located in the cerebral convexity and middle fossa demonstrated higher values in mean edema indices. The histologic subtypes meningothelial, anaplastic, microcystic, and angiomatous exhibited higher edema indices than other variants. [4] Several studies have put forward several hypotheses for pathogenesis of peritumoral edema in meningioma, such as the role of vascular endothelial growth factor and pial blood supply. All the three cases in this report showed contrast enhancement and perilesional edema.

Intraoperative diagnosis and classification of CNS tumors is difficult especially in small fragments that have been distorted due to freezing and cautery effect. Pathologist gives a diagnosis on intraoperative consultation based on clinical data, image findings, frozen section, and squash preparation. In cases 1 and 3, clinicoradiological data suggested an aggressive lesion and the operative findings suggested that the tumor is separated from the brain parenchyma. Frozen section and squash preparation showed the tumor to be quite bland though very vascular, hence frozen report was deferred until routine processing. In case 2, the clinician and radiologist had suggested the diagnosis of meningioma but the diagnosis was deferred until routine section evaluation because of the intense vascularity noted on frozen. The clinicoradiological feature did not correlate with frozen and squash findings hence, a more definitive intraoperative diagnosis could not be given in these cases.

Routine paraffin sections of all the three cases showed a tumor composed predominantly of blood vessels. The clinical data, radiological findings, and histopathological features were suggestive of either of the three lesions with a similar pattern; these were angiomatous meningioma, hemangioblastoma, and hemangiopericytoma. However, the dilemma was solved by immunohistochemistry workup as the tumor cells showed positive staining with EMA, cytokeratin, and progesterone confirming the diagnosis of meningioma. Angiomatous meningioma shows similar pattern of immunoreactivity as that of a typical meningioma. It shows positive staining with antibodies to vimentin, desmoplakin, and EMA, and focal positive reaction to antibodies to progesterone. Further confirmation may be done by electron microscopic study. Ultrastructurally, neoplastic meningeal cells have prominent cytoplasmic processes and well-defined junctions.

Martin et al. classified angiomatous meningioma into two patterns based on diameter of vessels as macrovascular with >50% of vessels having larger than 30 m in diameter and microvascular subtype in which >50% of vessels were smaller than 30 m in diameter. It is the microvascular pattern which can be confused with hemangioblastoma. [2] All the three cases showed a microvascular pattern with many foamy cells simulating a pattern seen in hemangioblastoma creating a dilemma for the pathologists. Angiomatous meningioma can have foamy cells which are related to leakage of plasma lipids across thin vessel wall. [2] A meningioma that is entirely hemangioblastic cannot be distinguished from hemangioblastoma except by its attachment to dura, immunohistochemical markers, and electron microscopy. [5]

WHO has subclassified all CNS tumors including meningioma into various grades. Meningiomas have been categorized into grades I, II, and III based on increased cellularity, high nucleocytoplasmic ratio, large prominent nucleoli, patternless sheets, mitosis, and spontaneous or geographic necrosis. Hence, a workup would be incomplete without the assessment of grade. Counting the mitotic figures is quite subjective and an objective method of evaluating proliferative activity is by performing Ki-67/MIB-1 immunostaining on tissue sections. Cases in this report had a MIB-1 index of <2% confirming them to be WHO grade I.

Capillary hemangioblastoma represents <1-2% of all CNS tumors and are mostly found in third to fifth decade. It occurs more commonly in cerebellum but can occur in brain stem and spinal cord, but a supratentorial location is rare. Computed tomography (CT) and MRI scans show a cystic lesion with an enhancing mural nodule. Microscopically, it is characterized by thin-walled blood vessels lined by plump endothelial cells and separate groups of polygonal stromal cells. These polygonal neoplastic cells contain vacuolated or foamy cytoplasm and nuclei may or may not show hyperchromasia and pleomorphism. But the tumor does not show any features of anaplasia. Vacuolated cells stain with fat stain on frozen section. The origin of this tumor is not completely understood.

Hemangiopericytomas are dural-based lesions which are often confused clinically with meningioma. Meningeal hemangiopericytoma was earlier described as angioblastic variant of meningioma, but it was Begg and Garret who recognized that it was in fact a hemangiopericytoma arising within meninges. [6] They account for 2-5% of meningeal lesions, occur commonly in adulthood and found more commonly in males. Image findings of hemangiopericytoma are similar to meningiomas. Microscopic examination show a highly vascular lesion composed of irregular cells with ill-defined cytoplasmic margins and staghorn vascular pattern. Reticulin stain delineates a dense meshwork in the pericellular region. Immunohistochemical stains play a vital role in differentiating hemangiopericytoma from angiomatous meningioma and hemangioblastoma. Hemangiopericytoma are immunoreactive to vimentin and endothelial antigen CD34 but stain negatively with EMA. Stromal cells of hemangioblastomas are immunoreactive to vimentin, neuron-specific enolase, S100, Glial fibriallary acidic protein, and calponin but fail to stain with EMA and prognosis is generally excellent. Kuruvilla and Madhavan have reported positivity with vascular endothelial markers, factor VIII R Ag and Ulex Europaeus A lectin 1 antibody (UEA-1) in both endothelial and stromal components of the tumor whereas a negative/faint reactivity in flattened endothelial lining of blood vessels in hemangiopericytomas. [7] The importance of differentiating these tumors needs to be emphasized due to the prognostic differences. Meningeal hemangiopericytomas are locally invasive lesions with recurrence rate higher than meningiomas.

Grade 1 meningiomas have a favorable prognosis. Since angiomatous meningioma belongs to this group, it has a similar behavior. Postoperative CT scans showed no residual tumor and the postoperative period was uneventful in the cases studied. To conclude we would like to summarize that angiomatous meningioma is a rare variant of meningioma with few distinctive clinical, radiological, histopathological, and immunohistochemical features. However, it may mimic other vascular neoplasms like hemangioblastoma or hemangiopericytoma creating a diagnostic dilemma and immunohistochemistry plays a vital role in distinguishing these lesions and confirming the final diagnosis.

 
   References Top

1.Kleihues P, Cavenee WK. World Health Organization classification of tumors. Pathology and genetics of tumors of the nervous system. Lyon: IARC Press; 2000. p.175-93.  Back to cited text no. 1    
2.Martin H, Kay WN, Werner P. Angiomatous meningioma - A clinicopathologic study of 38 cases. Am J Surg Pathol 2004;28:390-3.  Back to cited text no. 2    
3.Peter CB, James SN, Orest BB. Diagnostic synergy in radiology and surgical neuropathology. Arch Pathol Lab Med 1998;122:620-32.  Back to cited text no. 3    
4.Tamiya T, Ono Y, Matsumoto K, Ohmoto T. Peritumoral brain edema in intracranial meningiomas: effects of radiological and histological factors. Neurosurgery 2001;49:1046-51.  Back to cited text no. 4  [PUBMED]  [FULLTEXT]
5.Stacey E. Mills Sternberg's Diagnostic Surgical Pathology, 4 th ed. Lippincott William and Wilkins; 2004. p. 460-81.  Back to cited text no. 5    
6.Begg CF, Garret R. Hemangiopericytoma occurring in the meninges. Cancer 1954;7:602-6.  Back to cited text no. 6  [PUBMED]  
7.Sarah Kuruvilla, Malathy Madhavan. Diagnostic parameters of vascular neoplasms by immunohistochemistry. Indian J Pathol Microbiol 1992;35:180-7.  Back to cited text no. 7    

Top
Correspondence Address:
Sarah Kuruvilla
Department of Pathology, Sri Ramachandra Medical College and Research Institute, Porur, Chennai - 600 116, Tamil Nadu
India
Login to access the Email id


DOI: 10.4103/0377-4929.40397

PMID: 18417856

Get Permissions



    Figures

  [Figure - 1], [Figure - 2]
 
 
    Tables

  [Table - 1]

This article has been cited by
1 Hemangiopericytomas in the Spine
Huan-guang Liu,An-chao Yang,Ning Chen,Jun Yang,Xiao-guang Qiu,Jian-guo Zhang
Neurosurgery. 2013; 72(1): 16
[Pubmed]



 

Top
 
  Search
 
  
  
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Email Alert *
    Add to My List *
* Registration required (free)  


    Abstract
    Introduction
    Case History
    Discussion
    References
    Article Figures
    Article Tables

 Article Access Statistics
    Viewed5208    
    Printed114    
    Emailed4    
    PDF Downloaded376    
    Comments [Add]    
    Cited by others 1    

Recommend this journal