Papillary meningioma: clinical and histopathological observations

Abstract

Papillary meningioma is a rare subtype of malignant meningiomas, which is classified by the World Health Organization as Grade III. Because of lack of large sample size case studies, many of the specific characteristics of papillary meningioma are unclear. This study investigated by retrospective analysis the clinical, radiological and histopathological findings of 17 papillary meningioma patients who underwent surgical resection or biopsy, to assess the characteristics of papillary meningioma. Eight female and nine male patients were included, with a mean age of 40 (range: 6 to 55) years. Tumors were mostly located in the cerebral convexity and showed irregular margins, absence of a peritumoral rim, heterogeneous enhancement and severe peritumoral brain edema on preoperative images. Brain invasion was often confirmed during the operations, with abundant to exceedingly abundant blood supply. Intratumoral necrosis and mitosis was frequently observed on routinely stained sections. The average MIB-1 labeling index was 6.9%. Seven cases experienced tumor recurrence or progression, while seven patients died 6 to 29 months after operation. Radiation therapy was given in 52.9% of all cases. Univariate analysis showed that only the existence of intratumoral necrosis and incomplete resection correlated with tumor recurrence. The 3-year progression free survival was 66.7% after gross total resection and 63.6% for other cases. The 3-year mortality rate was 50% after gross total resection and 63.6% for other cases. Papillary meningioma has specific clinical and histopathological characteristics. Tumor recurrence (or progression) and mortality are common. Gross total tumor resection resulted in less recurrence and mortality.

Keywords: Papillary meningioma; clinical manifestations; histopathology; prognosis.

Figure 1

Sagittal and axial T1 (A and B), axial T2 (flair) (C) weighted, Sagittal and axial gadolinium enhanced (D, E and F) MR images of a right frontal papillary meningioma (case 7) with cystic change and large scale of PTBE (arrow). The tumor showed an irregular tumor margin with no peritumoral rim, and was heterogeneously enhanced. The cyst wall was not enhanced (arrowhead).

Figure 2

Preoperative sagittal and axial gadolinium enhanced MR images (A, B and D, E) and follow-up axial MR images (C and F) of two papillary meningiomas. A, B and C (6 months after operation), case 8; D, E and F (11 months after operation), case 1.

Figure 3

Microscopic manifestation of a papillary meningioma (case 4). A. perivascular pseudopapillary pattern (arrows) and mitosis (hollow arrow) shown on H&E sections; B. focal necrosis (*) shown on H&E sections; C. labeling of EMA; D. labeling of Vim; E. labeling of CKs; F. positivity with Ki-67 labeling (arrow head). Original magnification: ×400 for all sections.