Is Falcine Meningioma a Diffuse Disease of the Falx? Case Series and Analysis of a “Grade Zero” Resection

Abstract

BACKGROUND Falcine meningiomas have unique characteristics including their high rates of recurrence, association with high grade pathology, increased male prevalence, and potential for diffuse involvement of the falx. OBJECTIVE To address these issues in a substantial series of falcine meningiomas and report on the impact of extent of resection for this distinct meningioma entity. METHODS Retrospective analysis of characteristics and outcomes of 59 falcine meningioma patients who underwent surgery with the senior author. A “Grade Zero” category was used when an additional resection margin of 2 to 3 cm from the tumor insertion was achieved. RESULTS For de novo falcine meningiomas, gross total resection (GTR) was associated with significantly decreased recurrence incidence compared with subtotal resection (P ≤ .0001). For recurrent falcine meningiomas, median progression-free survival (PFS) was significantly improved for GTR cases (37 mo vs 12 mo; P = .017, hazard ratio (HR) .243 (.077-.774)). “Grade Zero” resection demonstrated excellent durability for both de novo and recurrent cases, and PFS was significantly improved with “Grade Zero” resection for recurrent cases (P = .003, HR 1.544 (1.156-2.062)). The PFS benefit of “Grade Zero” resection did not achieve statistical significance over Simpson grade 1 during the limited follow-up period (mean 2.8 yr) for these groups. CONCLUSION The recurrence of falcine meningiomas is related to the diffuse presence of tumor between the leaflets of the falx. Increased extent of resection including, when possible, a clear margin of falx surrounding the tumor base was associated with the best long-term outcomes in our series, particularly for recurrent tumors.

Topographic Distribution of Intracranial Meningioma’s Recurrences: Localized Versus Diffuse-Multicentric

“…These observations may explain some "unexpected relapses" after an apparent complete resection (Simpson grade 1) of convexity meningiomas [29] and the frequent peripheral recurrences at the dura surrounding the initial attachment after resection od Simpson grades 1 and 2 in all locations. These pathological findings support the concept of a wide dural excision 2-3 cm beyond the tumor base (grade zero resection), which was suggested for convexity [31] and falx meningiomas [32].…”

“…Mooney et al [32] suggest that in the falcine meningiomas the tumor cells may spread from the site of origin to other falx regions between the two dural leaflets of the falx. However, this pattern of diffusion of the tumor cells cannot explain the very distant recurrences from other locations.…”

Commentary in response to ‘Preoperative tumor embolization prolongs time to recurrence of meningiomas: a retrospective propensity-matched analysis’

“…In recent studies of WHO grade 1 meningiomas, the 5-year rate of recurrence after GTR is reported to be 5–10% and 20–30% after STR 2–4. Within Simpson 1 or Simpson ‘zero’ resection, recurrence for many grade 1 meningiomas should be nearly non-existent 5 6. The rates of recurrence in this study appear higher than prior studies, especially after STR, even compared with those that do not use embolization 3.…”

Falx Cerebelli Meningioma: Case Report of a Rarely Occurring Tumor, Management Nuances, and Literature Review

“…1 The posterior margin contains the occipital sinus, and it is attached to the lower surface of the tentorium cerebelli. 2 We report a case of a falx cerebelli meningioma that to our knowledge is the second documented case in the English literature.…”