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• Si has divergent effects on greenhouse gas production depending on redox conditions. • With oxidized OM and ferric Fe phases, Si addition led to higher P concentrations. • Oxidized OM showed higher CO 2 and CH 4 production rates under Si addition. • No effect of Si with reduced organic matter (OM) and without ferric Fe phases. Peatlands store about 30% of the global soil carbon (C) stock. The decomposition of peat C in these systems depends on environmental parameters – such as water table levels and corresponding availability of electron acceptors for microbial respiration. Due to the latter, potential peat decomposition depends also on whether the material is initially oxidized or reduced prior to decomposition experiments. Recent studies revealed the importance of silicon (Si) for peat decomposition. High amounts of biogenic Si were found in peatlands, in particular in minerotrophic fens, and the importance of Si for graminoids and decomposability of respective litter has been widely discussed. Furthermore, the availability of Si was reported to influence the binding of phosphorus (P) to iron (Fe) and thereby the conditions under which decomposition proceeds. Yet the influence of Si on greenhouse gas production in peat under different initial redox conditions is largely unknown. Therefore, we intended to test the effect of Si on greenhouse gas production under different initial electron acceptor availabilities for microbial respiration, such as the availability of ferric Fe. We conducted two incubation experiments with initially oxidized and reduced peat organic matter (OM). We hypothesized that Si can mobilize P from Fe minerals, which increases microbial activity, and leads to higher production rates of carbon dioxide (CO 2) and methane (CH 4). Using the two different materials, we studied how initial redox conditions would modify effects of Si. As the predominant form of Fe as either ferric Fe-(oxy)hydroxides or as ferrous Fe minerals (sulfides, carbonates) is important for interaction with Si, we further hypothesized that Si effects should be stronger in initially oxidized peat in presence of ferric Fe, compared to initially reduced peat with ferrous Fe only. For incubation experiments using formerly oxidized material the Si addition increased P concentrations in the pore water, and more CO 2 was produced. The onset of methanogenesis was much stronger with than without addition of Si, indicating a more rapid depletion of electron acceptors by faster rates of respiration. We explain this by more P being available stimulating microbial activity, and also by a direct effect of Si on microbial activity and methanogenesis. The incubation of formerly reduced OM did not show any effects of Si on respiration processes, presumably due to the absence of ferric Fe phases. In conclusion, there was a clear difference in the effect of Si addition on decomposition of formerly oxidized compared to long term reduced OM, with only oxidized peat OM or peat with ferric Fe phases present showing clear Si effects. Consequently, redox conditions and availability of ferric Fe are a main control for Si effects on OM decomposition and nutrient availability. Little effects of Si can be expected under permanently reducing conditions and in absence of ferric Fe phases. [ABSTRACT FROM AUTHOR]

Abstract: Syphilis is a sexually transmitted disease that can present a wide variety of clinical and histopathological manifestations. We present the case of a 75-year-old patient with a persistent maculopapular rash on the trunk and extremities, in which the biopsy showed an exclusively perifollicular granulomatous infiltrate. In the immunohistochemical staining with anti-Treponema pallidum antibodies, spirochetes scattered within the perifollicular inflammatory infiltrate were identified. These findings together with the serological analysis allowed the diagnosis of secondary syphilis. Folliculotropic nonalopecic syphilis is rare, and the pathogenic mechanisms that cause this specific tropism are unknown. On the other hand, granulomatous inflammation is a pattern typically described in tertiary syphilis but also occasionally found in secondary syphilis. We present a case of secondary syphilis with the combination of both histopathological findings, an uncommon constellation for dermatopathologists to consider., Competing Interests: The author declares no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Mycosis fungoides (MF) is defined as the most common cutaneous T‑cell lymphoma (CTCL). The bullous form is considered one of its numerous variants. Only a few cases of this rare entity have been described. We report the case of a man with an aggressive course of bullous MF, which led to lethal outcome within a few weeks due to a fulminant sepsis., (© 2024. The Author(s).)

This study investigates how amorphous silica (ASi) influences soil-plant-water interactions in distinct soil textures. A sandy loam and silty clay soil were mixed with 0 and 2% ASi, and their impact on soil retention and soil hydraulic conductivity curves were determined. In parallel, tomato plants (Solanum lycopersicum L.) were grown in experimental pots under controlled conditions. When plants were established, the soil was saturated, and a controlled drying cycle ensued until plants reached their wilting points. Soil water content, soil water potential, plant transpiration rate, and leaf water potential were monitored during this process. Results indicate a positive impact of ASi on the sandy loam soil, enhancing soil water content at field capacity (FC, factor of 1.3 times) and at permanent wilting point (PWP, a factor of 3.5 times), while its effect in silty clay loam was negligible (< 1.05 times). In addition, the presence of ASi prevented a significant drop in soil hydraulic conductivity ( K h ) at dry conditions. The K h of ASi-treated sandy loam and silty clay at PWP were 4.3 times higher than their respective control. Transpiration rates in plants grown in ASi-treated sandy loam soil under soil drying conditions were higher than in the control, attributed to improved soil hydraulic conductivity. At the same time, no significant difference was observed in the transpiration of plants treated with ASi in silty clay soil. This suggests ASi boosts soil-plant-water relationships in coarse-textured soils by maintaining heightened hydraulic conductivity, with no significant effect on fine-textured soils., (© 2024. The Author(s).)

Background and Objectives: Previous work has demonstrated that hydrochlorothiazide (HCTZ) is a risk factor for squamous cell carcinomas (SCC) and basal cell carcinomas (BCC) due to pro-photocarcinogenic effects. Atypical fibroxanthoma (AFX) and pleomorphic sarcoma (PDS), both ultraviolet-induced cancers, display a rare but rising cutaneous tumor entity. This study aimed to evaluate if the use of HCTZ is higher in patients with AFX/PDS than in patients with SCC/BCC and subsequently may be a risk factor for AFX/PDS-development., Patients and Methods: In a retrospective study of four German skin cancer centers, AFX/PDS cases and SCC/BCC controls were sex and age matched (1:3) over a time-period of 7 years (2013-2019) to evaluate the use of HCTZ, immunosuppressive medication, second malignancies, and presence of diabetes mellitus., Results: Overall, 146 AFX/PDS and 438 controls (SCC/BCC) were included in the study. The use of HCTZ was significantly higher in patients with AFX/PDS (44.5%) compared to patients with SCC/BCC (25.3%). Additionally, the presence of diabetes mellitus was significantly higher in AFX/PDS patients., Conclusions: This study demonstrates a significantly higher use of HCTZ in patients with AFX/PDS compared to SCC/BCC. This result suggests that HCTZ may be a risk factor for AFX/PDS. Additionally, diabetes mellitus or its comorbidities may be associated with an increased risk for AFX/PDS., (© 2024 The Authors. Journal der Deutschen Dermatologischen Gesellschaft published by Wiley‐VCH GmbH on behalf of Deutsche Dermatologische Gesellschaft.)

Elevated leaf silicon (Si) concentrations improve drought resistance in cultivated plants, suggesting Si might also improve drought performance of wild species. Tropical tree species, for instance, take up substantial amounts of Si, and leaf Si varies markedly at local and regional scales, suggesting consequences for seedling drought resistance. Yet, whether elevated leaf Si improves seedling drought performance in tropical forests is unknown. To manipulate leaf Si concentrations, seedlings of seven tropical tree species were grown in Si-rich and -poor soil, before exposing them to drought in the forest understorey. Survival, growth and wilting were monitored. Elevated leaf Si did not improve drought survival and growth in any of the species. In one species, drought survival was reduced in seedlings previously grown in Si-rich soil, contrary to our expectation. Our results suggest that elevated leaf Si does not improve drought resistance of wild tropical tree species. Elevated leaf Si may even reduce drought performance, suggesting differences in soil conditions influencing leaf Si may contribute to soil-related variation of tropical seedling performance. Furthermore, our results are at odds with most studies on cultivated species and show that alleviative effects of Si in crops cannot be generalized to wild plants in natural systems.

Background: Institutes of dermatopathology are faced with considerable challenges including a continuously rising numbers of submitted specimens and a shortage of specialized health care practitioners. Basal cell carcinoma (BCC) is one of the most common tumors in the fair-skinned western population and represents a major part of samples submitted for histological evaluation. Digitalizing glass slides has enabled the application of artificial intelligence (AI)-based procedures. To date, these methods have found only limited application in routine diagnostics. The aim of this study was to establish an AI-based model for automated BCC detection., Patients and Methods: In three dermatopathological centers, daily routine practice BCC cases were digitalized. The diagnosis was made both conventionally by analog microscope and digitally through an AI-supported algorithm based on a U-Net architecture neural network., Results: In routine practice, the model achieved a sensitivity of 98.23% (center 1) and a specificity of 98.51%. The model generalized successfully without additional training to samples from the other centers, achieving similarly high accuracies in BCC detection (sensitivities of 97.67% and 98.57% and specificities of 96.77% and 98.73% in centers 2 and 3, respectively). In addition, automated AI-based basal cell carcinoma subtyping and tumor thickness measurement were established., Conclusions: AI-based methods can detect BCC with high accuracy in a routine clinical setting and significantly support dermatopathological work., (© 2023 Deutsche Dermatologische Gesellschaft (DDG).)

Silicon-based defenses deter insect herbivores in many cultivated and wild grass species. Furthermore, in some of these species, silicon (Si) uptake and defense can be induced by herbivory. Tropical trees also take up Si and leaf Si concentrations vary greatly across and within species. As herbivory is a major driver of seedling mortality and niche differentiation of tropical tree species, understanding anti-herbivore defenses is pivotal. Yet, whether silicon is a constitutive and inducible herbivory defense in tropical forest tree species remains unknown. We grew seedlings of eight tropical tree species in a full factorial experiment, including two levels of plant-available soil Si concentrations (-Si/+Si) and a simulated herbivory treatment (-H/+H). The simulated herbivory treatment was a combination of clipping and application of methyl jasmonate. We then carried out multiple-choice feeding trials, separately for each tree species, in which leaves of each treatment combination were offered to a generalist caterpillar ( Spodoptera frugiperda ). Leaf damage was assessed. Three species showed a significant decrease in leaf damage under high compared to low Si conditions (by up to 72%), consistent with our expectation of Si-based defenses acting in tropical tree species. In one species, leaf damage was increased by increasing soil Si and in four species, no effect of soil Si on leaf damage was observed. Opposite to our expectation of Si uptake and defense being inducible by herbivory damage, simulated herbivory increased leaf damage in two species. Furthermore, simulated herbivory reduced Si concentrations in one species. Our results showed that tropical tree seedlings can be better defended when growing in Si-rich compared to Si-poor soils, and that the effects of Si on plant defense vary strongly across species. Furthermore, Si-based defenses may not be inducible in tropical tree species. Overall, constitutive Si-based defense should be considered part of the vast array of anti-herbivore defenses of tropical tree species. Our finding that Si-based defenses are highly species-specific combined with the fact that herbivory is a major driver of mortality in tropical tree seedling, suggests that variation in soil Si concentrations may have pervasive consequences for regeneration and performance across tropical tree species., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Klotz, Schaller and Engelbrecht.)

Increased crop production is a main goal to feed the predicted human population in future. The current management practice is, however, not sustainable as it depends on high amounts of fertilizer application and is highly vulnerable to decreased soil water availability. At the same time it becomes more and more crucial to reduce or even mitigate anthropogenic greenhouse gas (GHG) emissions. A possible way to enable this, might be the increase of the soil C sequestration and thus the C sink function of arable lands. A recent and potentially more sustainable idea is the single time fertilization with amorphous silicon (ASi) which is known to increase both nutrient and water availability. Here we show for the first time on the basis of a field plot experiment how a fertilization with ASi is affecting both, crop yield and the C sequestration of the soils in an agricultural system cultivating wheat. We found a strong increase in wheat yield and biomass production after ASi fertilization by increasing soil moisture during the whole growing season. Additionally, despite a relatively short growing season, Si fertilization increased the net C uptake by soils, i.e., C sequestration with both Si fertilized treatments showing a negative net ecosystem C balance (soil C gain) during the measurement period, while the control showed a small positive net ecosystem C balance (soil C loss). To our best knowledge, this is the first time such effect has ever been observed. In summary, our study demonstrates a new management strategy for crop production increasing yield and biomass production as well as soil C uptake on a more sustainable basis, by a single time fertilization with ASi., Competing Interests: Declaration of competing interest The authors declare no comparing interests. Experimental research and field studies on plants comply with relevant institutional, national, and international guidelines and legislation., (Copyright © 2023 Elsevier B.V. All rights reserved.)

For the majority of higher plants, silicon (Si) is considered a beneficial element because of the various favorable effects of Si accumulation in plants that have been revealed, including the alleviation of metal(loid) toxicity. The accumulation of non-degradable metal(loid)s in the environment strongly increased in the last decades by intensified industrial and agricultural production with negative consequences for the environment and human health. Phytoremediation, i.e., the use of plants to extract and remove elemental pollutants from contaminated soils, has been commonly used for the restoration of metal(loid)-contaminated sites. In our viewpoint article, we briefly summarize the current knowledge of Si-mediated alleviation of metal(loid) toxicity in plants and the potential role of Si in the phytoremediation of soils contaminated with metal(loid)s. In this context, a special focus is on metal(loid) accumulation in (soil) phytoliths, i.e., relatively stable silica structures formed in plants. The accumulation of metal(loid)s in phytoliths might offer a promising pathway for the long-term sequestration of metal(loid)s in soils. As specific phytoliths might also represent an important carbon sink in soils, phytoliths might be a silver bullet in the mitigation of global change. Thus, the time is now to combine Si/phytolith and phytoremediation research. This will help us to merge the positive effects of Si accumulation in plants with the advantages of phytoremediation, which represents an economically feasible and environmentally friendly way to restore metal(loid)-contaminated sites.

Arctic soils are the largest pool of soil organic carbon worldwide. Temperatures in the Arctic have risen faster than the global average during the last decades, decreasing annual freezing days and increasing the number of freeze-thaw cycles (temperature oscillations passing through zero degrees) per year as the temperature is expected to fluctuate more around 0 °C. At the same time, proceeding deepening of seasonal thaw may increase silicon (Si) and calcium (Ca) concentrations in the active layer of Arctic soils as the concentrations in the thawing permafrost layer might be higher depending on location. We analyzed the importance of freeze-thaw cycles for Arctic soil CO 2 fluxes. Furthermore, we tested how Si (mobilizing organic C) and Ca (immobilizing organic C) interfere with the soil CO 2 fluxes in the context of freeze-thaw cycles. Our results show that with each freeze-thaw cycle the CO 2 fluxes from the Arctic soils decreased. Our data revealed a considerable CO 2 emission below 0 °C. We also show that pronounced differences emerge in Arctic soil CO 2 fluxes with Si increasing and Ca decreasing CO 2 fluxes. Furthermore, we show that both Si and Ca concentrations in Arctic soils are central controls on Arctic soil CO 2 release, with Si increasing Arctic soil CO 2 release especially when temperatures are just below 0 °C. Our findings could provide an important constraint on soil CO 2 emissions upon soil thaw, as well as on the greenhouse gas budget of high latitudes. Thus we call for work improving understanding of freeze-thaw cycles as well as the effect of Ca and Si on carbon fluxes, as well as for increased consideration of those factors in wide-scale assessments of carbon fluxes in the high latitudes., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background and Objectives: In recent years, considerable insight has been gained into the pathogenesis, diagnosis and treatment of cutaneous sarcomas, including atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS). Both entities have shown increasing incidence rates in the last decade. This study was initiated to evaluate how these new insights impact the number of diagnoses of AFX/PDS compared to other cutaneous sarcoma entities., Patients and Methods: In a retrospective study of four German skin cancer centers, all histopathological reports of cutaneous sarcomas (AFX, PDS, dermatofibrosarcoma protuberans, cutaneous leiomyosarcoma, angiosarcoma, and Kaposi sarcoma) confirmed by board-certified dermatopathologists were analyzed during a time-period of seven years (2013-2019). Additionally, utilization of immunohistochemical markers (including pan-cytokeratin, S100, desmin, CD34, CD10, procollagen-1, CD99, CD14, and CD68) as an adjunct to diagnose AFX/PDS was recorded., Results: Overall, 255 cutaneous sarcomas were included in the present study. The diagnosis of a cutaneous sarcoma has consequently risen from 2013 to 2019 (from 16 to 52 annual cases). The results of AFX/PDS revealed 4.6 times more diagnoses in 2019 than in 2013. Atypical fibroxanthoma represented the most common subtype, displaying 49.3 % of all diagnosed cutaneous sarcomas. Additionally, the increase of AFX/PDS was linked to the use of immunohistochemistry, with specific immunohistochemical markers used in 57.1 % of cases in 2013 compared to 100 % in 2019., Conclusions: This retrospective study of four German skin cancer centers demonstrates a substantial rise of AFX/PDS, possibly due to recently established diagnostic and terminology standards. This rise is probably linked to increased utilization of specific immunohistochemical markers. Atypical fibroxanthoma/PDS may be more common than previously thought and seems to represent the most frequent cutaneous sarcoma subtype., (© 2022 The Authors. Journal der Deutschen Dermatologischen Gesellschaft published by John Wiley & Sons Ltd on behalf of Deutsche Dermatologische Gesellschaft.)

Hintergrund Und Ziele: In den letzten Jahren konnten umfassende Erkenntnisse über die Pathogenese, Diagnostik und Behandlung von kutanen Sarkomen, insbesondere des atypischen Fibroxanthoms (AFX) und pleomorphen dermalen Sarkoms (PDS) gesammelt werden. Beide Entitäten zeigten innerhalb der letzten Dekade steigende Inzidenzraten. Die vorliegende Studie diente der Untersuchung, welchen Einfluss die neuen Erkenntnisse auf die Fallzahlen von AFX/PDS im Vergleich zu anderen Sarkom-Entitäten haben., Patienten Und Methodik: Diese retrospektive Studie wurde an vier deutschen Hauttumorzentren durchgeführt und alle von zertifizierten Dermatopathologen bestätigten histopathologischen Befunde von kutanen Sarkomen (AFX, PDS, Dermatofibrosarcoma protuberans, kutanes Leiomyosarkom, Angiosarkom und Kaposi-Sarkom) in einem Zeitraum von sieben Jahren (2013-2019) evaluiert. Zusätzlich wurde der Einsatz von immunhistochemischen Markern als diagnostische Hilfe (Panzytokeratin, S100, Desmin, CD34, CD10, Prokollagen-1, CD99, CD14 und CD68) erfasst., Ergebnisse: Insgesamt konnten 255 kutane Sarkome in die vorliegende Studie eingeschlossen werden. Die Zahl der kutanen Sarkome nahm kontinuierlich von 2013 bis 2019 zu (von 16 auf 52 Fälle im Jahr). Die Diagnose eines AFX/PDS konnte in 2019 4,6-mal häufiger als in 2013 gestellt werden. Das AFX stellte mit 49,3 % aller kutanen Sarkome den häufigsten Sarkom-Subtypen dar. Zusätzlich war der Anstieg von AFX/PDS mit dem Einsatz von Immunhistochemie assoziiert. Der Einsatz von spezifischen Immunhistochemischen Markern stieg von 57,1 % im Jahr 2013 auf 100 % in 2019., Schlussfolgerungen: Diese retrospektive Studie von vier deutschen Hauttumorzentren demonstriert eine substanzielle Zunahme von AFX/PDS, wahrscheinlich infolge kürzlich etablierter beziehungsweise verbesserter diagnostischer und terminologischer Standards. Dieser Anstieg ist vermutlich mit dem vermehrten Einsatz von bestimmten immunhistochemischen Markern assoziiert. AFX/PDS treten wahrscheinlich häufiger auf als bisher vermutet und repräsentieren möglicherweise den häufigsten kutanen Sarkom-Subtyp., (© 2022 The Authors. Journal der Deutschen Dermatologischen Gesellschaft published by John Wiley & Sons Ltd on behalf of Deutsche Dermatologische Gesellschaft.)

Accurate classification of melanocytic tumors is important for prognostic evaluation, treatment and follow-up protocols of patients. The majority of melanocytic proliferations can be classified solely based on clinical and pathological criteria, however in select cases a definitive diagnostic assessment remains challenging and additional diagnostic biomarkers would be advantageous. We analyzed melanomas, nevi, Spitz nevi and atypical spitzoid tumors using parallel sequencing (exons of 611 genes and 507 gene translocation analysis) and methylation arrays (850k Illumina EPIC). By combining detailed genetic and epigenetic analysis with reference-based and reference-free DNA methylome deconvolution we compared Spitz nevi to nevi and melanoma and assessed the potential for these methods in classifying challenging spitzoid tumors. Results were correlated with clinical and histologic features. Spitz nevi were found to cluster independently of nevi and melanoma and demonstrated a different mutation profile. Multiple copy number alterations and TERT promoter mutations were identified only in melanomas. Genome-wide methylation in Spitz nevi was comparable to benign nevi while the Leukocytes UnMethylation for Purity (LUMP) algorithm in Spitz nevi was comparable to melanoma. Histologically difficult to classify Spitz tumor cases were assessed which, based on methylation arrays, clustered between Spitz nevi and melanoma and in terms of genetic profile or copy number variations demonstrated worrisome features suggesting a malignant neoplasm. Comprehensive sequencing and methylation analysis verify Spitz nevi as an independent melanocytic entity distinct from both nevi and melanoma. Combined genetic and methylation assays can offer additional insights in diagnosing difficult to classify Spitzoid tumors., (© 2022 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.)

Rice cultivation requires high amounts of phosphorus (P). However, significant amounts of P fertilizer additions may be retained by iron (Fe) oxides and are thus unavailable for plants. At the same time, rice cultivation has a high demand for silicic acid (Si), reducing Si availability after short duration of rice cultivation. By studying a paddy chronosequence with rice cultivation up to 2000 years, we show that Si limitation, observed as early as a few decades of rice cultivation, is limiting P availability along the paddy soils chronosequence. Using near edge X-ray absorption fine structure spectroscopy (NEXAFS) in a scanning transmission (soft) X-ray microscope (STXM) we show release of available P was linked to a Si-induced change in speciation of Fe-phases in soil particles and competition of Si with P for binding sites. Hence, low Si availability is limiting P availability in paddy soils. We propose that proper management of Si availability is a promising tool to improve the P supply of paddy plants., (© 2022. The Author(s).)

Drought and the availability of mineable phosphorus minerals used for fertilization are two of the important issues agriculture is facing in the future. High phosphorus availability in soils is necessary to maintain high agricultural yields. Drought is one of the major threats for terrestrial ecosystem performance and crop production in future. Among the measures proposed to cope with the upcoming challenges of intensifying drought stress and to decrease the need for phosphorus fertilizer application is the fertilization with silica (Si). Here we tested the importance of soil Si fertilization on wheat phosphorus concentration as well as wheat performance during drought at the field scale. Our data clearly showed a higher soil moisture for the Si fertilized plots. This higher soil moisture contributes to a better plant performance in terms of higher photosynthetic activity and later senescence as well as faster stomata responses ensuring higher productivity during drought periods. The plant phosphorus concentration was also higher in Si fertilized compared to control plots. Overall, Si fertilization or management of the soil Si pools seem to be a promising tool to maintain crop production under predicted longer and more serve droughts in the future and reduces phosphorus fertilizer requirements., (© 2021. The Author(s).)

Silicon (Si) accumulation is known to alleviate various biotic and abiotic stressors in plants with potential ecological consequences. However, for dicotyledonous plants our understanding of Si variation remains limited. We conducted a comparative experimental study to investigate (1) interspecific variation of foliar Si concentrations across 37 dicotyledonous forbs of temperate grasslands, (2) intraspecific variation in foliar Si concentration in response to soil Si availability, the influence of (3) phylogenetic relatedness, and (4) habitat association to moisture. Foliar Si differed markedly (approx. 70-fold) across the investigated forbs, with some species exhibiting Si accumulation similar to grasses. Foliar Si increased with soil Si availability, but the response varied across species: species with higher Si accumulation capacity showed a stronger response, indicating that they did not actively upregulate Si uptake under low soil Si availability. Foliar Si showed a pronounced phylogenetic signal, i.e., closely related species exhibited more similar foliar Si concentrations than distantly related species. Significant differences in foliar Si concentration within closely related species pairs nevertheless support that active Si uptake and associated high Si concentrations has evolved multiple times in forbs. Foliar Si was not higher in species associated with drier habitats, implying that in dicotyledonous forbs of temperate grasslands high foliar Si is not an adaptive trait to withstand drought. Our results demonstrated considerable inter- and intraspecific variation in foliar Si concentration in temperate forbs. This variation should have pervasive, but so far understudied, ecological consequences for community composition and functioning of temperate grasslands under land-use and climate change., (© 2021. The Author(s).)

Despite available vaccination, measles is one of the leading causes of death among young children in developing countries. In clinical practice, the spectrum of differential diagnoses of morbilliform exanthemas associated with fever is wide, and it can be hard to differentiate from other infectious eruptions, especially in adults or in atypical courses in immunocompromised patients. The goal of our study was to identify characteristic histomorphological and immunohistochemical patterns of measles exanthema through the study of 13 skin biopsy specimens obtained from 13 patients with this disease and a review of cases in the literature. Histopathological features of measles exanthema are quite distinctive and characterized by a combination of multinucleated keratinocytes, and individual and clustered necrotic keratinocytes in the epidermis with pronounced folliculosebaceous as well as acrosyringeal involvement. Immunohistochemical staining of skin biopsies with anti-measles virus (MeV) nucleoprotein and anti-MeV phosphoprotein can be of great value in confirming the diagnosis of measles. Both methods can serve as quick additional diagnostic tools for prompt implementation of quarantine measures and for providing medical assistance, even in patients in whom the clinician did not consider measles as a differential diagnosis of the rash due to the rarity of the disease in a putatively vaccinated community.

An otherwise healthy 50-year-old woman was evaluated for the presence of 2 erythematous, and slightly pruritic plaques, involving both cheeks for 30 years. Left-side skin biopsy showed a diffuse proliferation of ductal structures horizontally arranged and involving the reticular dermis that resembled tubular adenoma embedded in a sclerotic stroma and surrounded by a peculiar periductal desmoplasia. Nuclear atypia or mitosis was not found. Contralateral biopsy showed identical findings. Differential diagnosis included microcystic adnexal carcinoma (MAC) and plaque-like syringoma and a peculiarly horizontally arranged tubular adenoma. We ruled out MAC as the lesions were long-standing, without infundibular cysts, solid strands, or perineural infiltration. Our case closely resembled those previously described as sweat duct proliferation associated with aggregates of elastic tissue and atrophoderma vermiculatum, although striking differences were observed, as our case did not present aggregates of elastic tissue, did not involve the papillary and superficial reticular dermis, and presented evidences of decapitation secretion as a sign of apocrine differentiation. We consider our case as a MAC simulator and we propose the descriptive name of bilateral facial apocrine fibrosing hamartoma.

Atypical fibroxanthomas and pleomorphic dermal sarcomas are tumors arising in sun-damaged skin of elderly patients. They have differing prognoses and are currently distinguished using histological criteria, such as invasion of deeper tissue structures, necrosis and lymphovascular or perineural invasion. To investigate the as-yet poorly understood genetics of these tumors, 41 atypical fibroxanthomas and 40 pleomorphic dermal sarcomas were subjected to targeted next-generation sequencing approaches as well as DNA copy number analysis by comparative genomic hybridization. In an analysis of the entire coding region of 341 oncogenes and tumor suppressor genes in 13 atypical fibroxanthomas using an established hybridization-based next-generation sequencing approach, we found that these tumors harbor a large number of mutations. Gene alterations were identified in more than half of the analyzed samples in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter. The presence of these alterations was verified in 26 atypical fibroxanthoma and 35 pleomorphic dermal sarcoma samples by targeted amplicon-based next-generation sequencing. Similar mutation profiles in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter were identified in both atypical fibroxanthoma and pleomorphic dermal sarcoma. Activating RAS mutations (G12 and G13) identified in 3 pleomorphic dermal sarcoma were not found in atypical fibroxanthoma. Comprehensive DNA copy number analysis demonstrated a wide array of different copy number gains and losses, with similar profiles in atypical fibroxanthoma and pleomorphic dermal sarcoma. In summary, atypical fibroxanthoma and pleomorphic dermal sarcoma are highly mutated tumors with recurrent mutations in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter, and a range of DNA copy number alterations. These findings suggest that atypical fibroxanthomas and pleomorphic dermal sarcomas are genetically related, potentially representing two ends of a common tumor spectrum and distinguishing these entities is at present still best performed using histological criteria.

The present CME article highlights fundamental aspects with respect to the histopathology of the most common skin tumors (epidermal, adnexal, melanocytic, and mesenchymal), their laboratory workup, as well as the importance of supplementary immunohistochemical and molecular studies. The information provided is meant to assist experienced clinicians in choosing the correct biopsy technique and in interpreting dermatopathology reports, and to provide dermatology residents with a better understanding of dermatopathology. Similar to inflammatory dermatoses, the diagnosis of skin tumors, too, requires the close cooperation between clinicians and dermatopathologists. The diagnostic quality and the resultant therapeutic approach can be significantly improved if this collaboration is based on the same dermatological understanding., (© 2017 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.)

In diesem CME-Artikel werden histopathologische Grundkenntnisse der häufigsten Hauttumoren (epidermal, adnexiell, melanozytär, mesenchymal), deren labortechnische Aufarbeitung sowie der Stellenwert immunhistochemischer und molekularer Zusatzuntersuchungen zusammengefasst. Dies soll dem erfahrenen Kliniker bei der Wahl der richtigen Entnahmetechnik und der Interpretation der histopathologischen Befundberichte behilflich sein und in dermatologischer Weiterbildung befindlichen Ärzten ein besseres Verständnis der Dermatohistologie vermitteln. Ähnlich wie bei den entzündlichen Dermatosen sind auch in der Diagnostik von Hauttumoren Kliniker und Dermatohistopathologen aufeinander angewiesen und können die Qualität der Diagnostik und der daraus resultierenden therapeutischen Verständnisbasis deutlich verbessern., (© 2017 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.)

Die Dermatohistologie ist von unverzichtbarem Stellenwert in der Diagnostik entzündlicher und neoplastischer Hautveränderungen. Zur richtigen Einordnung und Interpretation der histologischen Befunde, der Durchführung klinisch-pathologischer Korrelationen (insbesondere bei entzündlichen Hauterkrankungen) sowie für die Wahl der richtigen Exzisionsmethode sind grundlegende Kenntnisse in der Dermatohistologie für den praktisch tätigen Dermatologen wertvoll und steigern die diagnostische Qualität. In diesem Artikel wird die Vorgehensweise des Dermatopathologen in der Diagnostik entzündlicher Dermatosen beschrieben. Anhand wichtiger histologischer Grundmuster werden die Grundprinzipien der dermatohistologischen Diagnostik erläutert. Ein folgender zweiter Teil wird die histologischen Charakteristika der häufigsten Hauttumoren darstellen., (© 2017 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.)

Dermatopathology is an indispensable tool in the diagnostic workup of inflammatory and neoplastic lesions. For the dermatologist in everyday clinical practice, basic knowledge of dermatopathology is highly valuable, as it allows for proper classification and interpretation of histological findings, as well as their correlation with the clinical picture (especially in case of inflammatory skin diseases). Such basic understanding is also important with regard to selecting the appropriate biopsy technique, thus increasing the overall diagnostic quality. The present article describes the diagnostic approaches taken by dermatopathologists in the histological workup of inflammatory skin diseases. The basic principles of this workup are highlighted on the basis of key histological patterns. Published in an upcoming issue, the second part of this article will address the histological characteristics of the most common skin tumors., (© 2017 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.)

Einleitung: Das Pyoderma gangraenosum (PG) ist eine seltene, inflammatorische destruktiv-ulzerierende neutrophile Erkrankung mit weitgehend unklarer Pathophysiologie., Material Und Methodik: In dieser Studie wurden die potenziell relevanten Kofaktoren und Begleiterkrankungen von Patienten mit PG aus drei dermatologischen Wundzentren in Deutschland differenziert ausgewertet., Ergebnisse: Von den insgesamt 121 analysierten Patienten waren Frauen (66,9 %) häufiger betroffen als Männer. Das Alter der Patienten war 18-96 Jahre (Mittelwert [MW]: 59,8); die Wunden hatten eine Größe von 1-600 cm² (MW: 65,6 cm²) und waren überwiegend sehr schmerzhaft (VAS 1-10, MW: 7). Die Unterschenkel waren am häufigsten (71,9 %) betroffen. Bei 12 (9,9 %) Patienten bestanden chronisch entzündliche Darmerkrankungen (5,8 % Colitis ulcerosa; 4,1 % Morbus Crohn), bei 14,1 % der Patienten wurde eine Begleiterkrankung aus dem rheumatischen Formenkreis beschrieben. Neoplasien bestanden bei 20,6 % der Patienten, von denen 6,6 % als hämatologische und 14,1 % als solide Neoplasien klassifiziert wurden. Aus dem Kreis des metabolischen Syndroms wurde bei 69,4 % Patienten eine Adipositas, bei 57,9 % eine arterielle Hypertonie und bei 33,9 % ein Diabetes mellitus diagnostiziert., Schlussfolgerungen: Diese Datenanalyse bestätigt Assoziationen des PG mit dem metabolischen Syndrom und mit Neoplasien, die zukünftig frühzeitig bei einer zielgerichteten Diagnostik der Patienten beachtet und behandelt werden sollten., (© 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.)

Plant diversity is an important driver of nitrogen and phosphorus stocks in aboveground plant biomass of grassland ecosystems, but plant diversity effects on other elements also important for plant growth are less understood. We tested whether plant species richness, functional group richness or the presence/absence of particular plant functional groups influences the Si and Ca concentrations (mmol g(-1)) and stocks (mmol m(-2)) in aboveground plant biomass in a large grassland biodiversity experiment (Jena Experiment). In the experiment including 60 temperate grassland species, plant diversity was manipulated as sown species richness (1, 2, 4, 8, 16) and richness and identity of plant functional groups (1-4; grasses, small herbs, tall herbs, legumes). We found positive species richness effects on Si as well as Ca stocks that were attributable to increased biomass production. The presence of particular functional groups was the most important factor explaining variation in aboveground Si and Ca stocks (mmol m(-2)). Grass presence increased the Si stocks by 140 % and legume presence increased the Ca stock by 230 %. Both the presence of specific plant functional groups and species diversity altered Si and Ca stocks, whereas Si and Ca concentration were affected mostly by the presence of specific plant functional groups. However, we found a negative effect of species diversity on Si and Ca accumulation, by calculating the deviation between mixtures and mixture biomass proportions, but in monoculture concentrations. These changes may in turn affect ecosystem processes such as plant litter decomposition and nutrient cycling in grasslands.