28 November 2012 - Case #259
All cases are archived on our website. To view them sorted by case number, diagnosis or category, visit our main Case of the Month page. To subscribe or unsubscribe to Case of the Month or our other email lists, click here.
Thanks to Dr. Eman Abdelzaher, Alexandria University (Egypt), for contributing this case and the discussion.
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Case #259
Clinical history:
A 45 year old woman had an MRI for headache, which showed a dural-based extra-axial lesion of the left parietal region, with dural enhancement and surrounding grade II vasogenic edema. At surgery, the lesion was red and richly vascular. Gross total excision was performed.
Macroscopic examination showed multiple brownish soft tissue fragments (2.5 x 1 x 0.5 cm in aggregate) with a spongy appearance.
Microscopic images:
What is your diagnosis?
Diagnosis: Microcystic meningioma, WHO grade I
Immunostains:
Discussion:
The tumor was strongly immunoreactive for EMA.
The microscopic images reveal a loosely textured pattern created by intra- and intercellular microcystic spaces. Scattered cells with pleomorphic hyperchromatic nuclei are seen, as well as thickened blood vessels with hyalinized walls. Focal xanthomatous change is present.
Microcystic meningioma is a variant of meningioma characterized by cells with thin, elongate processes encompassing microcysts. Pleomorphic cells, xanthomatous change and thick walled blood vessels are common. Accompanying cerebral edema and macrocysts may be seen. It has benign behavior and corresponds to WHO grade I, with no prognostic significance assigned.
Microcystic meningioma (especially in a pure form) frequently creates diagnostic problems because of the minimal morphological clues of its meningothelial nature. Recognition requires awareness of its existence. Meningioma should always be considered for supratentorial extra-axial enhancing lesions. Histological clues to diagnosis include a loosely textured pattern with microcysts, nuclear pleomorphism and thick walled hyalinized blood vessels. EMA staining is confirmatory.
The differential diagnosis includes:
In the case under discussion, the supratentorial extra-axial location, contrast enhancement, characteristic histopathological features and immunoreactivity for EMA were all in favor of microcystic meningioma. The tumor did not show atypical features and it was assigned to grade I.
References: IARC: WHO Classification of Tumours of the Central Nervous System, 4th Edition, 2007, Acta Neurochir (Wien) 2005;147:965
All cases are archived on our website. To view them sorted by case number, diagnosis or category, visit our main Case of the Month page. To subscribe or unsubscribe to Case of the Month or our other email lists, click here.
Thanks to Dr. Eman Abdelzaher, Alexandria University (Egypt), for contributing this case and the discussion.
This months recommended article
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and function in cystic fibrosis airway epithelial cells:
Role of ezrin and the RhoA/ROCK pathway
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(1) Don't forget to make your online purchases at Amazon.com by first clicking on one of our Home Page Amazon.com banners, or a link on the Books pages, or by clicking here.
(2) We posted two new articles on our Management Page: Missing Accession Audit Process, by Diana Brooks, PSA, LLC, and Changes in the Anatomic Pathology Billing World, by Mick Raich, President, Vachette Pathology.
Visit and follow our Blog to see recent updates to the website.
Case #259
Clinical history:
A 45 year old woman had an MRI for headache, which showed a dural-based extra-axial lesion of the left parietal region, with dural enhancement and surrounding grade II vasogenic edema. At surgery, the lesion was red and richly vascular. Gross total excision was performed.
Macroscopic examination showed multiple brownish soft tissue fragments (2.5 x 1 x 0.5 cm in aggregate) with a spongy appearance.
Microscopic images:
What is your diagnosis?
Click here for diagnosis and discussion:
Diagnosis: Microcystic meningioma, WHO grade I
Immunostains:
Discussion:
The tumor was strongly immunoreactive for EMA.
The microscopic images reveal a loosely textured pattern created by intra- and intercellular microcystic spaces. Scattered cells with pleomorphic hyperchromatic nuclei are seen, as well as thickened blood vessels with hyalinized walls. Focal xanthomatous change is present.
Microcystic meningioma is a variant of meningioma characterized by cells with thin, elongate processes encompassing microcysts. Pleomorphic cells, xanthomatous change and thick walled blood vessels are common. Accompanying cerebral edema and macrocysts may be seen. It has benign behavior and corresponds to WHO grade I, with no prognostic significance assigned.
Microcystic meningioma (especially in a pure form) frequently creates diagnostic problems because of the minimal morphological clues of its meningothelial nature. Recognition requires awareness of its existence. Meningioma should always be considered for supratentorial extra-axial enhancing lesions. Histological clues to diagnosis include a loosely textured pattern with microcysts, nuclear pleomorphism and thick walled hyalinized blood vessels. EMA staining is confirmatory.
The differential diagnosis includes:
- Pilocytic astrocytoma: young age, usually posterior fossa, intra-axial, biphasic pattern, Rosenthal fibers, eosinophilic granular bodies, GFAP+
- Hemangioblastoma: rarely supratentorial, usually posterior fossa, rich reticulin network, EMA-, inhibin+
- Metastatic carcinoma: anaplasia, mitosis, necrosis, CK+
In the case under discussion, the supratentorial extra-axial location, contrast enhancement, characteristic histopathological features and immunoreactivity for EMA were all in favor of microcystic meningioma. The tumor did not show atypical features and it was assigned to grade I.
References: IARC: WHO Classification of Tumours of the Central Nervous System, 4th Edition, 2007, Acta Neurochir (Wien) 2005;147:965
