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

Meningiomas recur with a rate of 10–32% at ten years. Several features influence the risk of recurrence. Our aim is to define the pathological and surgical features at risk of diffuse-multicentric versus local-peripheral recurrence. Thirty-three cases of multicentric-diffuse recurrence of intracranial meningiomas were retrospectively analyzed and compared with 50 cases who experienced local-peripheral recurrence. The analyzed factors included age and sex, tumor location and shape, brain-tumor interface, entity of resection, WHO grade, Ki67 MIB1, progesterone receptor (PR) expression, number of reoperations, progression of WHO grade, and outcome. The multicentric-diffuse recurrences were mainly related to flat-shaped and Ki67 Li greater than 4% features at first surgery. Among patients with multicentric-diffuse recurrences, 25 underwent one to three reoperations; among them, 17 are alive with local tumor control or slow progression 2 to 25 years after the initial surgery versus only 2 out of 8 who did not undergo surgery. We conclude that flat-shaped meningiomas and those with Ki67 Li greater than 4% are at higher risk to recur in multicentric-diffuse pattern. Even multiple reoperations over a period of several years may obtain rather long survivals in selected patients with prevalent intradural not anaplastic tumors and not too extensive dural infiltration.

Volcano dynamics vs tectonics on Mars: evidence from Pavonis Mons

<p>Volcanic activity is widespread within the inner Solar system and it can be commonly observed on rocky planets.<br>In this work, we analyse the structures of Pavonis Mons, which is one of the three large volcanoes in the Tharsis volcanic province of Mars, by performing structural mapping, azimuth, and topographic distribution of linear features on the flanks of Pavonis, such as grabens and pit chains. We tested whether their formation is to be ascribed to the internal volcano dynamics and magmatic activity or the tectonics related to the Tharsis volcanic province activity.<br>Through the length size distribution and fractal clustering analyses of the structural features, we found that large grabens are vertically confined in the upper mechanical layers of the brittle crust whereas pit chains penetrate the whole crust up to the magmatic source, indicating that they can be considered the main feeders of Pavonis Mons. We inverted the topography with dykes and faults models to test whether grabens at the surface are the expression of intrusions at depth and we suggest that thin dykes inducing normal faulting is the most likely mechanism. Furthermore, two azimuthal distribution of the grabens are identified: concentric grabens occur on the volcano summit while linear grabens at its base show NE-SW trend as the Tharsis Montes volcanoes alignment. The analyses show that faults related to large grabens are confined in a mechanical layering in the upper layers of the brittle crust, whereas deeper structures such as pit chains are most likely associated to magma injection/dykes and therefore, connected to the subcrustal magma source at a depth of ~80–100 km.<br>Therefore, based on our results, we infer that Pavonis Mons recorded active rifting at the initial stages of development with the formation of the large linear graben and faults at its base followed by a phase of volcano growth and concentric magma intrusions when volcano and magma chamber dynamics prevailed</p>

Topographic Distribution of Carious Lesion on Young Permanent Mandibular Molars and Its Relation to Periapical Index Score of Apical Periodontitis: A Radiographic Analysis

INTRODUCTION: Caries in young permanent teeth progress rapidly resulting in early pulp involvement which further progresses into loss of mineralized tissue and severe periapical pathologies. The Periapical Index scoring system (PAI) proposed by Ørstavik et al. in 1986 is an invaluable diagnostic tool used to evaluate periapical lesion extent and severity by 2D digital intraoral periapical radiographic analysis with minimal radiation exposure and hence treatment planning.AIM: To evaluate the relationship of the surface distribution of caries in young permanent molars, pulpal involvement and periapical index (PAI) score with respect to individual root forming young permanent mandibular molars. MATERIALS AND METHOD: In this retrospective single-centre study, 100 pulpally involved carious young permanent mandibular molars were included, selected from the departmental records between August 2018-2019. Topographic distribution of caries and radiographic analysis (using PAI) was evaluated to see the effect of anatomical site of caries, individual anatomical form of root, and extent & severity of apical periodontitis developed.RESULT: No significant correlation between the site of caries involvement and PAI score was observed. PAI score for distal roots was higher(PAI> 2) as compared to mesial root for pulpally involved carious young permanent first molars (p-value mesial root-0.576 , distal root-0.591)CONCLUSION: PAI score is independent of the topographic distribution of caries and no correlation was observed. Periapical radiolucency does not depend on caries distribution, either it is mesial, distal or occlusal.