Journal Article

P11.05 Whorling-sclerosing type of meningioma. CD34 and P53 IHC-positivity with lack of malignant features in a rare meningioma type

R. Sari, F. H. Bolukbasi, M. Onoz, O. Baskan, M. A. Altinoz, A. Sav and I. Elmaci

in Neuro-Oncology

Volume 18, issue suppl_4, pages iv66-iv66
Published in print October 2016 | ISSN: 1522-8517
Published online September 2016 | e-ISSN: 1523-5866 | DOI: http://dx.doi.org/10.1093/neuonc/now188.236
P11.05 Whorling-sclerosing type of meningioma. CD34 and P53 IHC-positivity with lack of malignant features in a rare meningioma type

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Intoduction:

Whorling-Sclerosing variant of meningioma (WSM) with unique morphology may be considered as a high-grade meningioma due to its partial brain invasion; yet malignant behavior of this tumor is not reported. The term “whorling” is being used to define different morphological features including psammoma bodies formed by precipitated calcium or by layered whorling sheets of tumor cells in meningothelial meningiomas. In WSM, the whorling and sclerosing structures are formed by - almost completely acellular - collagen. Recognizing this rare variant may help to distinguish these tumors from malignant meningiomas and to prevent needless treatment.

Materials and Methods:

We defined morphological and immunohistochemical features of such a tumor in detail.

Results:

Abundant whorls of collagen were witnessed confirmed with Masson Trichrome staining. Reticulin matrix was present. In parallel to the previous literature, tumor stained positively with epithelial membrane antigen EMA (Score: 4+), S100 protein (Score: 4+ in meningothelial area), vimentin (Score: 4+ in meningothelial; 2+ in sclerotic area) and negatively with GFAP. Pancytokeratin was highly (Score: 4+) present in whorling-sclerosing regions. The meningothelial regions exerted cellular whorling areas with psammoma and pseudopsammoma patterns. Infiltrating CD45+ lymphocytes (Score:2+) were present. Stromal and vascular hyalinization was observed and the existing vessels had a regular basal membrane. In opposite to previous reports, the tumor was positive for p53 (Score: 3+) and CD34 (Score: 3+). However, no histopathological signs of aytpia or malignancy were observed including hypercellularity, micronecrosis, geographical necrosis, small cells and prominent nucleoli. Cell nuclei exerted invaginations. At x10 magnification, mitotic index was less than 4% and the average Ki67 index was 3,67%. Furthermore; in contrast to previous reports on this tumor, progesterone receptor was found to be expressed, which was several times shown as a sign of differentiated and less-aggressive tumor behavior in meningiomas.

Conclusions:

Recognizing this rare type of meningioma may help to avoid unnecessary examinations and treatments.

Journal Article.  0 words. 

Subjects: Medical Oncology ; Neurology

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