Integrative Approach Uncovers New Patterns of Ecomorphological Convergence in Slow Arboreal Xenarthrans

Identifying ecomorphological convergence examples is a central focus in evolutionary biology. In xenarthrans, slow arboreality independently arose at least three times, in the two genera of ‘tree sloths’, Bradypus and Choloepus, and the silky anteater, Cyclopes. This specialized locomotor ecology is expectedly reflected by distinctive morpho-functional convergences. Cyclopes, although sharing several ecological features with ‘tree sloths’, do not fully mirror the latter in their outstandingly similar suspensory slow arboreal locomotion. We hypothesized that the morphology of Cyclopes is closer to ‘tree sloths’ than to anteaters, but yet distinct, entailing that slow arboreal xenarthrans evolved through ‘incomplete’ convergence. In a multivariate trait space, slow arboreal xenarthrans are hence expected to depart from their sister taxa evolving toward the same area, but not showing extensive phenotypical overlap, due to the distinct position of Cyclopes. Conversely, a pattern of ‘complete’ convergence (i.e., widely overlapping morphologies) is hypothesized for ‘tree sloths’. Through phylogenetic comparative methods, we quantified humeral and femoral convergence in slow arboreal xenarthrans, including a sample of extant and extinct non-slow arboreal xenarthrans. Through 3D geometric morphometrics, cross-sectional properties (CSP) and trabecular architecture, we integratively quantified external shape, diaphyseal anatomy and internal epiphyseal structure. Several traits converged in slow arboreal xenarthrans, especially those pertaining to CSP. Phylomorphospaces and quantitative convergence analyses substantiated the expected patterns of ‘incomplete’ and ‘complete’ convergence for slow arboreal xenarthrans and ‘tree sloths’, respectively. This work, highlighting previously unidentified convergence patterns, emphasizes the value of an integrative multi-pronged quantitative approach to cope with complex mechanisms underlying ecomorphological convergence.

BAP1-deficient meningioma presenting with trabecular architecture and cytokeratin expression: a report of two cases and review of the literature

AimsBRCA (BReast CAncer gene)-associated protein 1 (BAP1), encoded by the BAP1 gene, a tumour suppressor that is lost in several cancers. Importantly, such mutations have been shown to be susceptible to poly (ADP-ribose) polymerase (PARP) inhibition in preclinical studies, offering hope for targeted therapy. While rare, BAP1 loss has been observed in a subset of rhabdoid and papillary meningioma and is associated with earlier recurrence. We seek to add to the literature on this rare disease and advocate for more routine BAP1 testing.MethodsWe present a report of two cases of BAP1-deficient meningioma and review the available literature on this rare entity.ResultsBoth cases present with a distinct trabecular architecture without rhabdoid or papillary features. Interestingly, both also presented with radiographic and histopathological findings unusual for meningioma. While immunohistochemistry and genetic sequencing confirmed BAP1 loss, DNA methylation analysis was required to confirm the final diagnosis.ConclusionsWe suggest that BAP1-deficient meningioma should be considered in the differential diagnosis of extra-axial central nervous system (CNS) tumours with atypical imaging or histopathological features and that BAP1 loss may constitute a clinically important meningioma subtype with opportunities for targeted therapy.

Why heel spurs are traction spurs after all

It is unclear whether plantar and posterior heel spurs are truly pathological findings and whether they are stimulated by traction or compression forces. Previous histological investigations focused on either one of the two spur locations, thereby potentially overlooking common features that refer to a uniform developmental mechanism. In this study, 19 feet from 16 cadavers were X-ray scanned to preselect calcanei with either plantar or posterior spurs. Subsequently, seven plantar and posterior spurs were histologically assessed. Five spur-free Achilles tendon and three plantar fascia entheses served as controls. Plantar spurs were located either intra- or supra-fascial whereas all Achilles spurs were intra-fascial. Both spur types consistently presented a trabecular architecture without a particular pattern, fibrocartilage at the tendinous entheses and the orientation of the spur tips was in line with the course of the attached soft tissues. Spurs of both entities revealed tapered areas close to their bases with bulky tips. Achilles and plantar heel spurs seem to be non-pathological calcaneal exostoses, which are likely results of traction forces. Both spur types revealed commonalities such as their trabecular architecture or the tip direction in relation to the attached soft tissues. Morphologically, heel spurs seem poorly adapted to compressive loads.

Osteonecrosis of the jaw induced by treatment with anti-PD-1 immunotherapy: a case report

Recognizing rare but clinically significant toxicity of immunotherapy is critical. Here we describe the first detailed case of severe osteonecrosis of the jaw due to anti-PD-1. A 75-year-old man with metastatic melanoma, with no prior radiation or treatment with bone-targeting agents, experienced jaw pain 1 week after his first dose of nivolumab. Imaging studies were negative, and treatment was resumed after pain was controlled. 4 months later, the patient experienced acute exacerbation of pain and malocclusion of the jaw. Imaging showed bilateral fractures of the angle of mandible with extensive disruption of the normal trabecular architecture, requiring total mandibulectomy. The patient’s metastatic melanoma responded to treatment and remains controlled >20 months after treatment cessation without further therapy.