Case No.: N-021

Diagnosis: Angiomatous meningioma, WHO grade I

Organ: Brain, Parasagittal

Last Updated: 3/21/2011

   

Online Slide/Full Screen/Open with ImageScope

 
Online Slide/Full Screen/Open with ImageScope

Hematoxylin & eosin

Area 1: The tumor is highly vascular and have lots of stromal cells. The cytologic features of the neoplastic cells (arrow) are suggestive of a hemangioblastoma but the overall architecture is not classic for hemangioblastoma. Note that the nuclei of some of the neoplastic cells are slightly enlarged, hyperchromatic but lack a prominent nucleoli.

Hematoxylin & eosin

Area 2: The changes are similar to area 1 except that many of the smaller blood vessels are sclerotic and hyalinized.

Hematoxylin & eosin

Area 3: Note psammoma bodies are present (arrow head). You can see more psammoma bodies in other part of this slide. The histologic picture is dominated by sclerotic, hyalinized blood vessels with islands of neoplastic cells (arrow) in between.

Hematoxylin & eosin

Area 4: This area is a mixture of both sclerotic blood vessels and microcyst formation.

Hematoxylin & eosin

Area 5: In comparison to area 4, microcysts and sclerotic blood vessels are intermixed with each other and there seems to be more microcystic area than sclerotic blood vessels.

History: The patient was a 62 year-old woman with an extra-axial parasagittal mass that has been followed by the neurosurgery clinics for some time. There was slow increase in size and the mass was excised and yielded the current lesion.

 

Imaging: On MRI scan, there is a dural based, parafalcine mass, 2.5 cm in greatest dimension, with vasogenic edema in the surrounding brain parenchyma. The mass enhances brightly. There was also associated dural thickening and enhancement along the falx.

MRI T1-Contrast

Histologic Highlights of this Case:

  • The received specimen consists of rather rubbery fragments of tan, light brown tissue fragments. They are rather cohesive and no cytologic preparation was performed at the time of frozen section.

  • Slide #1 represent the tissue that are received at the time of frozen. Only half of the tissue was submitted for frozen and the slide being shown here represents the portion that have not been frozen. This specimen appears to be a highly vascular lesion with quite a good amount of stromal cells in between (area 1 and 2). Note that the stromal cells have hyperchromatic nuclei but no prominent nucleoli. There are no intranuclear inclusions or high grade pleomorphism. No definitive clear cells were observed. Definitive sclerotic changes are present in many of the blood vessels.

  • Slide #2 represent the tissue that are submitted subsequently. The histopathology between this sample and slide #1 is essentially similar but the there are a lot more highly sclerotic blood vessels. Some calcifications consistent with psammoma bodies are present (area 3). The sclerotic blood vessels dominated the picture. In between the sclerotic vessels are triangular to irregular nest of stromal cells (area 3). Microcyst formation is rather common (area 4 and 5).

  • Mitotic figures are not readily seen.

Histopathology:

  • Cytokeratin: Negative in all components.

  • Inhibit: Negative in all components.

  • Epithelial membrane antigen (EMA): Negative in all components.

  • Glut1: Positive in endothelial cells and stromal cell component.

  • CD31: Positive in endothelial cells and negative in stromal cells.

  • CD34: Positive in endothelial cells and negative in stromal cells.

Discussion:

  • The overall histopathologic picture is that of an angiomatous meningioma. These tumor are featured by hypervascularity and often with degenerative changes of the vessels including vascular hyalinization as illustrated in this case. The nuclei tends to undergo degenerative atypia (ancient changes) featured by slightly enlarged, homogeneously hyperchormatic nuclei without prominent nucleoli and not associated with increased mitosis. The neoplastic meningothelial proliferation often has microcystic pattern as illustrated here.

  • EMA is often but not always positive in meningioma and it is negative in this case. A lack of immuoreactivity for EMA does not rule out a diagnosis of meningioma. One of the possibile explanation for the lack of EMA immunoreactivity in this case is that EMA immunoreactivity is often patchy in meningioma. The total volume of meningothelial proliferation is not that much in this case and the bulk of the tumor is either blood vessels or empty spaces in the microcysts.

  • The main differential diagnosis of this case is hemangioblastoma. Slide #1 have features quite suspicious of hemangioblastoma. Cerebral hemisphere is not the most common one for hemangioblastoma and they are not typically dural based. Their incidence in descending order is cerebellum (80%) followed by the medulla and spinal cord. The location and MRI findings, however, are very typical for a meningioma. Hemangioblastoma often, but not always, have clear cells. Their blood vessels are typically delicate rather than hyalinized. The histologic features, particularly the microcystic changes, degenerative atypia of nuclei, and sclerotic blood vessels, are also in favor of angiomatous meningioma. The psammoma bodies are also good clue for meningioma. Hemangioblastoma is often immunoreactive for inhibin which is negative in this case. Glut1 immunoreactivity in hemangioblastoma should be positive in endothelial cells and negative in stromal cells. The current case is positive in both component. The negative immunoreactivity for cytokeratin and the overall histopathology also rule out the possibility of a metastatic carcinoma.

Original slide is contributed by Dr. Kar-Ming Fung, University of Oklahoma Health Sciences Center, Oklahoma, U.S.A.

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