Salivary gland hyalinizing clear‐cell carcinoma with cutaneous metastasis: A rare and deceptive tumor

Clear‐cell carcinoma (CCC) is an uncommon malignant tumor of minor salivary glands. It characteristically has a low‐grade morphology and a favorable outcome by most reports. An EWSR1‐ATF1 fusion can be detected in the majority of cases. We present a rare case of CCC, which had an aggressive course with the development of cutaneous metastases. Practicing dermatopathologists should be aware of this tumor given its low‐grade appearance and histopathologic resemblance to other primary cutaneous adnexal and metastatic neoplasms.     

Panniculitis in a 3‐year‐old child with Fanconi anemia‐associated bone marrow hypoplasia heralds transformation to acute myeloid leukemia

Fanconi anemia is a rare, autosomal recessive genomic instability disorder characterized by congenital limb anomalies, panmyelopathy and a high risk of malignancy, principally acute myeloid leukemia. Hematologic malignancy presenting with acute febrile neutrophilic dermatosis (Sweet syndrome), both deep and superficial forms, is well described in Fanconi anemia patients but is a rare phenomenon in otherwise healthy children. We present a case of panniculitis (presumptive subcutaneous Sweet syndrome) heralding transformation to acute myeloid leukemia in a 3‐year‐old boy with a severe Fanconi anemia phenotype.     

Mutant C9orf72 human iPSC-derived astrocytes cause non-cell autonomous motor neuron pathophysiology

Mutations in C9orf72 are the most common genetic cause of amyotrophic lateral sclerosis (ALS). Accumulating evidence implicates astrocytes as important non-cell autonomous contributors to ALS pathogenesis, although the potential deleterious effects of astrocytes on the function of motor neurons remains to be determined in a completely humanized model of C9orf72-mediated ALS. Here, we use a human iPSC-based model to study the cell autonomous and non-autonomous consequences of mutant C9orf72 expression by astrocytes. We show that mutant astrocytes both recapitulate key aspects of C9orf72-related ALS pathology and, upon co-culture, cause motor neurons to undergo a progressive loss of action potential output due to decreases in the magnitude of voltage-activated Na⁺ and K⁺ currents. Importantly, CRISPR/Cas-9 mediated excision of the C9orf72 repeat expansion reverses these phenotypes, confirming that the C9orf72 mutation is responsible for both cell-autonomous astrocyte pathology and non-cell autonomous motor neuron pathophysiology.     

Suicide vs medical assistance in dying (MAiD): A secondary qualitative analysis

Abstract

This is a secondary analysis of three qualitative studies about MAiD in which researchers asked about the differences between suicide and MAiD. In all, researchers interviewed 52 Canadians; 7 were people who had requested MAiD and had been found ineligible, 6 were MAiD providers and 39 were socially and economically marginalized. The overwhelming response was that MAiD is better than suicide in the context of suffering at the end of life. Whereas these people perceived suicide as uncertain, difficult, and something that was usually done alone and without support, they thought MAiD was certain, painless, and more socially acceptable.     

Top‐down versus bottom‐up attention differentially modulate frontal–parietal connectivity

The moment‐to‐moment focus of our mind's eye results from a complex interplay of voluntary and involuntary influences on attention. Previous neuroimaging studies suggest that the brain networks of voluntary versus involuntary attention can be segregated into a frontal‐versus‐parietal or a dorsal‐versus‐ventral partition—although recent work suggests that the dorsal network may be involved in both bottom‐up and top‐down attention. Research with nonhuman primates has provided evidence that a key distinction between top‐down and bottom‐up attention may be the direction of connectivity between frontal and parietal areas. Whereas typical fMRI connectivity analyses cannot disambiguate the direction of connections, dynamic causal modeling (DCM) can model directionality. Using DCM, we provide new evidence that directed connections within the dorsal attention network are differentially modulated for voluntary versus involuntary attention. These results suggest that the intraparietal sulcus exerts a baseline inhibitory effect on the frontal eye fields that is strengthened during exogenous orienting and attenuated during endogenous orienting. Furthermore, the attenuation from endogenous attention occurs even with salient peripheral cues when those cues are known to be counter predictive. Thus, directed connectivity between frontal and parietal regions of the dorsal attention network is highly influenced by the type of attention that is engaged.