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Con la “Single Cell Biology”1 una nuova era è iniziata e con essa il nostro modo di di capire i processi biologici è stato rivoluzionato. In breve si tratta di misurare la stessa caratteristica in ogni singola cellula di un campione, non semplicemente estrarre il dato come una media fra tutte. Questa rivoluzione aggiunge un nuovo livello di risoluzione a quello che possiamo “vedere” e ci permette di comprendere meglio la complessità di un campione composto da diverse entità: le cellule. Caratterizzare singolarmente le cellule ci permette di approfondire la nostra conoscenza rispetto a fenotipo, sviluppo e network. Tutto questo è possibile grazie allo sviluppo di nuove tecnologie: le “single cell-omic technologies". Tra tutte queste novità la proteomica spaziale rappresenta un piccolo ma cruciale settore per diverse ragioni: la risoluzione a singola cellula è associata alla localizzazione spaziale, si misura la presenza di proteine e non RNA (quindi segnali dopo le modifiche trascrizionali), vengono analizzate tutte le cellule senza perderne determinati tipi come spesso succede nella disgregazione dei tessuti o in altre tecnologie a singola cellula, infine consente studi retrospettivi utilizzando campioni Fissati in Formalina e Inclusi in Paraffina (FFPE) ed è facilmente integrabile con altre tecnologie “-omiche”. Nel 2017 abbiamo sviluppato e pubblicato un lavoro metodologico chiamato Multiple Iterative Labeling by Antibody Neodeposition (MILAN technology) “che consiste nella colorazione multipla dello stesso campione di tessuto con diversi anticorpi..” 2 La tesi di dottorato si sviluppa in questo scenario. In pratica concerne l’analisi, con la tecnologia MILAN, di tessuti umani e murini, sani e patologici, a risoluzione cellulare, per classificare, quantificare e localizzare in situ le diverse popolazioni cellulari e per identificarne le specifiche interazioni e caratteristiche. Raccoglie gli articoli significativi di questi 3 anni di ricerca che hanno seguito la pubblicazione del metodo MILAN. La prima parte contiene l'applicazione di MILAN su due differenti tipi di tessuti. In una casistica di Leiomiosarcomi Uterini è stato caratterizzato l’infiltrato infiammatorio; in un modello murino di Fibrosi Polmonare Idiopatica (IPF) sono state identificate le diverse popolazioni cellulari nel polmone, misurata la loro presenza in percentuale e la loro espressione di un trasportatore transmembrana. Questi due articoli rappresentano l'applicazione del metodo a due livelli differenti e il suo utilizzo per rispondere a specifiche domande scientifiche. Segue un articolo che contiene una panoramica sulle tecnologie disponibili per immunoistochimica/immunofluorescenza con approccio multiplex, vantaggi e svantaggi, il confronto con la tecnologia MILAN. Fornisce inoltre i principi base per interpretare dati high-dimensional nel loro contesto spaziale. Poi, per analizzare un grosso data set di tessuti linfoidi, mancando uno specifico algoritmo di analisi, ne abbiamo creato uno nuovo: BRAQUE ovvero Bayesian Reduction for Amplified Quantization in Umap Embedding. Questo algoritmo è specificamente pensato per analizzare dati prodotti da immagini in immunofluorescenza multiplex. Infine l’ultima parte del progetto è dedicata alla classificazione a singola cellula del tessuto linfoide umano, su una casistica di circa 100 linfonodi, colorati e analizzati con più di 80 marcatori. Il progetto è ancora in corso, tuttavia negli ultimi due capitoli sono presentati risultati preliminari. I dati delle popolazioni identificate saranno integrati con dati provenienti da single-cell RNA sequencing. 1. Schier, A. F. Single-cell biology: beyond the sum of its parts. Nat. Methods 17, 17–20 (2020). 2. Bolognesi, M. M. et al. Multiplex Staining by Sequential Immunostaining and Antibody Removal on Routine Tissue Sections. J. Histochem. Cytochem. 65, 431–444 (2017). The field of Single Cell biology 1 has revolutionized the way we understand biological processes and a new era is started. In a few words it can be explained as the detection of the same traits in every single cell inasample,notjustasthemeanvalueofthebulk.Thisrevolutionhasaddeda new level of resolution to what we can “see” and makes us better understand the complexity of a sample made of different entities: cells. Characterization of single cells has increased our understanding of cell phenotypes, the dynamics and trajectory of their development, and their network. All of this has been possible thanks to the fast development of a large group of technologies: “single-cell multi omic technologies”. Among all of these novelties high-plex spatial proteomic represents a small but crucial niche for many reasons: it has a single cell resolution associated with spatial localization, it evaluates the presence of protein and not RNA signal (bypassing post transcriptional modification), it analyses whole cells without losing any types of them as often happens in tissue disaggregation or other single cell technologies, it allows retrospective study on Formalin Fixed Paraffin Embedded (FFPE) sample collection, easily integrable with other -omic technologies. In 2017 we developed a method called Multiple Iterative Labeling by Antibody Neodeposition (MILAN technology) “Which implies multiple stainings of a tissue section with multiple antibodies..” 2 Within this scenario my PhD thesis develops. Briefly it concerns the analysis, with MILAN technology, of human or mouse, healthy or pathologic tissues, at single cell level in order to classify cell populations, quantify and localize them in situ and recognize their specific interaction and characteristics. It’s a selection of results of these 3 last years of research after the publication of the MILAN technology method. The first part is related to the application of MILAN methods to different types of tissue. This has allowed us to characterize immune infiltrate presence in a rare dataset of Uterine leiomyosarcomas and to identify cell population in a mouse model of Idiopathic Pulmonary Fibrosis (IPF) by measuring percentage of population and their expression as a drug transporter. These papers represent the application of methods at different levels and its use to answer specific scientific questions. Subsequently an overview of the available technologies for multiplex immunohistochemistry is presented with “their advantages and challenges, the comparison with MILAN, and provide the basic principles on how to interpret high-dimensional data in a spatial context.” Then, because of the availability of a large lymphoid tissue image data set, for which there were no present specific algorithms, we created the” Bayesian Reduction for Amplified Quantization in Umap Embedding” (BRAQUE) algorithm, a tailored pipeline of analysis for data coming from highly multiplexed imaging data sets. The last part of the project is dedicated to the classification at single cell level of normal human lymph nodes with the previously created bioinformatic tool BRAQUE. This has been possible thanks to a huge effort of sample collection and analysis of almost 100 samples stained with more than 80 antibodies. Even if the project is still ongoing, we have already obtained some interesting results presented in chapter 5-6 (manuscripts in preparations). The database of lymph nodes cell populations will be subsequently integrated with scRNAseq data. 1. Schier, A. F. Single-cell biology: beyond the sum of its parts. Nat. Methods 17, 17–20 (2020). 2. Bolognesi, M. M. et al. Multiplex Staining by Sequential Immunostaining and Antibody Removal on Routine Tissue Sections. J. Histochem. Cytochem. 65, 431–444 (2017).

Artificial intelligence is getting a foothold in medicine for disease screening and diagnosis. While typical machine learning methods require large labeled datasets for training and validation, their application is limited in clinical fields since ground truth information can hardly be obtained on a sizeable cohort of patients. Unsupervised neural networks – such as Self-Organizing Maps (SOMs) – represent an alternative approach to identifying hidden patterns in biomedical data. Here we investigate the feasibility of SOMs for the identification of malignant and non-malignant regions in liquid biopsies of thyroid nodules, on a patient-specific basis. MALDI-ToF (Matrix Assisted Laser Desorption Ionization - Time of Flight) mass spectrometry-imaging (MSI) was used to measure the spectral profile of bioptic samples. SOMs were then applied for the analysis of MALDI-MSI data of individual patients’ samples, also testing various pre-processing and agglomerative clustering methods to investigate their impact on SOMs’ discrimination efficacy. The final clustering was compared against the sample's probability to be malignant, hyperplastic or related to Hashimoto thyroiditis as quantified by multinomial regression with LASSO. Our results show that SOMs are effective in separating the areas of a sample containing benign cells from those containing malignant cells. Moreover, they allow to overlap the different areas of cytological glass slides with the corresponding proteomic profile image, and inspect the specific weight of every cellular component in bioptic samples. We envision that this approach could represent an effective means to assist pathologists in diagnostic tasks, avoiding the need to manually annotate cytological images and the effort in creating labeled datasets.

Lymphomatous infiltration of kidney parenchyma is a frequent complication of systemic hematologic malignancies and often shows subtle clinical presentation. Diffuse large B-cell lymphoma represents the most frequent form involving the kidney, with advanced stage at diagnosis, poor outcome, and risk for central nervous system relapse if not adequately treated. Kidney biopsy can provide specific and early detection of these cases, helping in the differential diagnosis with more frequent entities. Finally, further hematologic workup (bone marrow biopsy, complete blood cell count, and positron emission tomography) can distinguish secondary involvement of the kidney from the rarer kidney-limited forms, especially in patients without a previous diagnosis of lymphoma. Making a prompt and correct diagnosis directs the management of these cases and may improve the outcome, as described in the present report.

International audience; The interest in implementing digital pathology (DP) workflows to obtain whole slide image (WSI) files for diagnostic purposes has increased in the last few years. The increasing performance of technical components and the Food and Drug Administration (FDA) approval of systems for primary diagnosis led to increased interest in applying DP workflows. However, despite this revolutionary transition, real world data suggest that a fully digital approach to the histological workflow has been implemented in only a minority of pathology laboratories. The objective of this study is to facilitate the implementation of DP workflows in pathology laboratories, helping those involved in this process of transformation to identify: (a) the scope and the boundaries of the DP transformation; (b) how to introduce automation to reduce errors; (c) how to introduce appropriate quality control to guarantee the safety of the process and (d) the hardware and software needed to implement DP systems inside the pathology laboratory. The European Society of Digital and Integrative Pathology (ESDIP) provided consensus-based recommendations developed through discussion among members of the Scientific Committee. The recommendations are thus based on the expertise of the panel members and on the agreement obtained after virtual meetings. Prior to publication, the recommendations were reviewed by members of the ESDIP Board. The recommendations comprehensively cover every step of the implementation of the digital workflow in the anatomic pathology department, emphasizing the importance of interoperability, automation and tracking of the entire process before the introduction of a scanning facility. Compared to the available national and international guidelines, the present document represents a practical, handy reference for the correct implementation of the digital workflow in Europe.

Digital pathology for the routine assessment of cases for primary diagnosis has been implemented by few laboratories worldwide. The Gravina Hospital in Caltagirone (Sicily, Italy), which collects cases from 7 different hospitals distributed in the Catania area, converted the entire workflow to digital starting from 2019. Before the transition, the Caltagirone pathology laboratory was characterized by a non-tracked workflow, based on paper requests, hand-written blocks and slides, as well as manual assembling and delivering of the cases and glass slides to the pathologists. Moreover, the arrangement of the spaces and offices in the department was illogical and under-productive for the linearity of the workflow. For these reasons, an adequate 2D barcode system for tracking purposes, the redistribution of the spaces inside the laboratory and the implementation of the whole-slide imaging (WSI) technology based on a laboratory information system (LIS)-centric approach were adopted as a needed prerequisite to switch to a digital workflow. The adoption of a dedicated connection for transfer of clinical and administrative data between different software and interfaces using an internationally recognised standard (Health Level 7, HL7) in the pathology department further facilitated the transition, helping in the integration of the LIS with WSI scanners. As per previous reports, the components and devices chosen for the pathologists’ workstations did not significantly impact on the WSI-based reporting phase in primary histological diagnosis. An analysis of all the steps of this transition has been made retrospectively to provide a useful “handy” guide to lead the digital transition of “analog”, non-tracked pathology laboratories following the experience of the Caltagirone pathology department. Following the step-by-step instructions, the implementation of a paperless routine with more standardized and safe processes, the possibility to manage the priority of the cases and to implement artificial intelligence (AI) tools are no more an utopia for every “analog” pathology department.

Background: The implementation of a fully digital workflow in any anatomic pathology department requires a complete conversion to a tracked system. Ensuring the strict correspondence of the material submitted for the analysis, from the accessioning to the reporting phase, is mandatory in the anatomic pathology laboratory, especially when implementing the digital pathology for primary histological diagnosis. The proposed solutions, up to now, rely on the verification that all the materials present in the glass slide are also present in the whole slide images (WSIs). Although different methods have already been implemented for this purpose (e.g., the 'macroimage' of the digital slide, representing the overview of the glass slide), the recent introduction of a device to capture the cut surface of paraffin blocks put the quality control of the digital workflow a step forward, allowing to match the digitized slide with the corresponding block. This system may represent a reliable, easy-to-use alternative to further reduce tissue inconsistencies between material sent to the lab and the final glass slides or WSIs. Methods: The Anatomic Pathology of the Gravina Hospital in Caltagirone, Sicily, Italy, has implemented the application of the BlocDoc devices (SPOT Imaging, Sterling Heights, USA) in its digital workflow. The instruments were positioned next to every microtome/sectioning station, with the possibility to capture the 'normal' and the polarized image of the cut surface of the blocks directly by the technician. The presence of a monitor in the BlocDoc device allowed the technician to check the concordance between the cut surface of the block and the material on the corresponding slide. The link between BlocDoc and the laboratory information system, through the presence of the 2D barcode, allowed the pathologists to access the captured image of the cut surface of the block at the pathologist workstation, thus enabling the direct comparison between this image and the WSI (thumbnail and 'macroimage'). Results: During the implementation period, more than 10.000 (11.248) blocks were routinely captured using the BlocDoc. The employment of this approach allowed a drastic reduction of the discordances and tissue inconsistencies. The implementation of the BlocDoc in the routine allowed the detection of two different types of 'errors,' the so-called 'systematic' and 'occasional' ones. The first type was intrinsic of some specific specimens (e.g., transurethral resection of the prostate, nasal polypectomies, and piecemeal uterine myomectomies) characterized by the three-dimensional nature of the fragments and affected almost 100% of these samples. On the other hand, the 'occasional' errors, mainly due to inexperience or extreme caution of the technicians in handling tiny specimens, affected 98 blocks (0.9%) of these samples and progressively reduced with the rising confidence with the BlocDoc. One of these cases was clinically relevant. No problems in the recognition of the 2D barcodes were encountered using a laser cassette printer. Finally, rare failures have been recorded during the period, accounting for

In melanoma, the lymphocytic infiltrate is a prognostic parameter classified morphologically in “brisk”, “non-brisk” and “absent”. The meaning of “brisk” is “active, energetic”, implying a functional connotation which has never been proved. Recently, it has been shown that not all brisk infiltrates have a good prognosis, that lymphocytic populations can be very heterogeneous, and that anti-PD-1 immunotherapy supports activated T cells. Here, we characterize the immune landscape in primary melanoma by high-dimensional single cell multiplex analysis in tissue sections (MILAN technique) followed by image analysis, RT-PCR and shotgun proteomics. We observed that the brisk and non-brisk patterns of tumor infiltrating lymphocytes (TILs) in primary melanoma are heterogeneous functional categories that can be further sub-classified according to the functional status of their lymphocytes as active, transitional or exhausted. We found that only activation of TILs correlates with spontaneous regression, and that the good prognosis of melanomas with a brisk pattern could be due to the fact that in these case the Tcy that are in contact with the melanoma cells are still active, and consequently the melanoma is still under immune control at the moment of surgical excision. The main inflammatory cell subpopulations that are present in the microenvironment associated with activation and exhaustion and their spatial relationships are described using neighbourhood analysis. Finally, we show a bioinformatic pipeline that, starting from common immunofluorescence stainings, can transform the tissue into a digitalized image, which represents the starting point for multiple deeper levels of analysis.

Objective: This paper analyzes a series of ultrasound (US)-guided orbital fine needle aspirations (FNAs) which provide diagnostic information that cytopathologists approaching orbital lesions for the first time can find useful and underlines the importance of teamwork. Study Design: The investigators retrospectively obtained data from 24 consecutive orbital FNAs. For all patients, a complete clinicoradiological database was created. FNAs were performed under US guidance with 25-gauge needles and an aspiration biopsy syringe gun, and sent to the Department of Pathology for examination and data management. Results: The mean age of the patients was 54 years. Imaging studies included US, magnetic resonance imaging and computed tomography scans; 9 lesions involved the right orbit and 15 the left orbit. The mean lesion size was 23.6 ± 7.2 mm. After microscopic examination, 7 smears were labeled as ‘nondiagnostic', while in 17 cases a definitive diagnosis was proposed, which always proved to be correct (70.8%, specificity = 100%). Conclusions: The investigators believe that FNA biopsy of orbital masses is a necessary step; its weaknesses lie in the particularly delicate site of sampling and the extreme heterogeneity of lesions. Nevertheless, when orbital FNA is performed within a well-coordinated multidisciplinary team, it is a powerful tool that can be used to define the most appropriate management of these patients.

Mutations in MYH9 gene encoding the nonmuscle myosin heavy chain IIA (NMMHC-IIA) are related to a number of rare autosomal-dominant disorders which has been known as May-Hegglin disease, Sebastian syndrome, Fechtner syndrome and Epstein syndrome. Their common clinical features are congenital macrothrombocytopaenia and polymorphonuclear inclusion bodies, in addition to a variable risk of developing proteinuria, chronic kidney disease progressing toward end stage, sensorineural deafness and presenile cataracts. The term MYH9 related disease (MYH9-RD) describes the variable expression of a single illness encompassing all previously mentioned hereditary disorders. Renal involvement in MYH9- RD has been observed in 30% of patients. Mutant MYH9 protein, expressed in podocytes, mesangial and tubular cells, plays a main role in foot process effacement and in development of nephropathy. Interestingly, the MYH9 gene is currently under investigation also for his possible contribution to many other non-hereditary glomerulopathies such as focal global glomerulosclerosis (hypertensive nephrosclerosis), idiopathic focal segmental glomerulosclerosis, C1q nephropathy and HIV-associated nephropathy. In this review we are aimed to describe renal diseases related to MYH9 disorders, from the hereditary disease to the acquired disorders, in which MYH9-gene acts as a "renal failure susceptibility gene".

The objective of this study was to evaluate the clinical features, prognostic factors, and efficacy of treatments in patients with blastic plasmacytoid dendritic cell neoplasm with a leukemic presentation at onset of the disease. In order to do this, a retrospective multicenter study was performed from 2005-2011 in 28 Italian hematology divisions in which 43 cases were collected. Forty-one patients received an induction therapy, consisting of an acute myeloid leukemia-type regimen in 26 patients (60%) and acute lymphoid leukemia/lymphoma-type regimen in 15 patients (35%). Six patients (14%) underwent allogeneic hematopoietic stem cell transplantation. Seventeen patients (41%) achieved a complete remission: seven after acute myeloid leukemia-type treatment and 10 after an acute lymphoid leukemia/lymphoma-type regimen, with a significant advantage for acute lymphoid leukemia/lymphoma-type chemotherapy (P=0.02). Relapse occurred in six of the 17 patients (35%) who achieved complete remission, more frequently after acute lymphoid leukemia/lymphoma-type chemotherapy. The median overall survival was 8.7 months (range, 0.2-32.9). The patients treated with an acute myeloid leukemia-type regimen had an overall survival of 7.1 months (range, 0.2-19.5), whereas that of the patients receiving acute lymphoid leukemia/lymphoma-type chemotherapy was 12.3 months (range, 1-32.9) (P=0.02). The median overall survival of the allogeneic hematopoietic stem cell transplant recipients was 22.7 months (range, 12-32.9), and these patients had a significant survival advantage compared to the non-transplanted patients (median 7.1 months, 0.2-21.3; P=0.03). In conclusion, blastic plasmacytoid dendritic cell neoplasm with bone-marrow involvement is an aggressive subtype of high-risk acute leukemia. The rarity of this disease does not enable prospective clinical trials to identify the better therapeutic strategy, which, at present, is based on clinicians' experience.

IgG4 related disease is a systemic fibro-inflammatory disorder characterized by multiple organ and multiple tissue lesions. The real pathogenesis is currentlyactually unknown. For these reasons many authors compare IgG4 related disease to sarcoidosis. Lesions are often localized in the pancreas, salivary and lacrimal glands, biliary ducts, retroperitoneum and in many other organs. The diagnosisis difficult because of mild symptoms and the possibility of mimicking other severe diseases. Therefore, histopathology together with clinical and radiological typical findings are mandatory tools for diagnosis. Steroidtherapy usually enables disappearance of tumor like lesions and complete recovery. Kidney has an extensive organ involvement in the contextof IgG4-related disease. Historically, tubule - interstitial nephritis(TIN) is considered the main renal feature of renal lesions, however recent studies extend the spectrum of renal lesions also to glomerular tuft. These findings allow to introduce in the nosography the term of IgG4related kidney disease (IgG4 RKD). This review focuses on renal involvement in IgG4related disease, in order to help nephrologists to improve their clinical, diagnostic and therapeutic approach to this emerging pleiotropic clinical pattern.

Human papillomaviruses (HPVs) are necessary, but not sufficient, for the development of cervical cancer (CC). Human β-herpesviruses (β-HHVs) have been suggested as possible cofactors in the oncogenesis of CC. In this cross-sectional study, the prevalence and possible association of cytomegalovirus (CMV), HHV-6 and -7 with HPV presence was investigated by quantitative real-time PCR assays in cervical samples obtained from 208 italian women. The two most common high-risk HPV types found were 31 and 16. Overall, the positive rates for CMV, HHV-6 and HHV-7 were 66%, 25%, and 6%, respectively. In particular, the prevalence of CMV was found to be extremely high irrespective of either the cytological category or HPV positivity. The prevalence of HHV-6 DNA was significantly higher in high-grade squamous intraepithelial lesions (HSIL) respect to normal women (P

Dear Sir,Most of the rarer causes of chorea have been clarified in thelast decades [1], so that the classic term of ‘‘idiopathicchorea’’ has been critically put into question.A 50-year-old Caucasian woman was referred formarked and progressive generalized chorea. The onset wasabout 1 year before and a depressive syndrome was alsopresent. Past medical and family histories were unre-markable. Slight dysarthria and adiadochokinesia werenoted. Ocular movements were normal. Deep tendonreflexes were diffusely enhanced and plantar response wasin extension bilaterally. Routine serology, ceruloplasmin,tumour markers, HIV serology, onconeural- and auto-antibodies were negative. The anti-streptolysin-O titre wasborderline and careful examination of blood smears failedto demonstrate acanthocytes. A magnetic resonance and a99mTc-ECD SPECT brain scans were not significant. Theneuropsychological assessment evidenced only minorimpairment in selective attention and slight dysexecutivenotes. Genetic testing for Huntigton’s disease (HD, 17/25triplets), DRPLA (150/150), SCA17 (36/37), SCA1 (21/30), SCA2 (23/23), SCA3 (20/22), SCA6 (11/12), SCA7(9/11), and FXTAS (23/23) were negative. Progranulin andPRNP mutations or C9orf72 expansions were absent. Anti-basal ganglia antibodies (ABGA) testing (courtesy ofDr. Giovannoni and Martino, UCL, UK) resulted in a weakpositive binding to pyruvate kinase M1 (60 kDa), while nobinding was shown for both gamma-neuron specific eno-lase, and aldolase C.Since neuroleptics were ineffective, a trial with high-dose IV steroids was attempted, with no immediateimprovement (HD Functional Capacities score: 2/13, stageIV; Folstein Chorea Scale score: 37/57). Three monthslater, only minor changes were noted (HDFCS: 3/13, stageIV; FCS: 27/57). The patient further deteriorated present-ing diffuse spasticity and dystonia. Due to worseningdysphagia the patient was referred for PEG positioning, butshe anyhow died of aspiration pneumonia about 4 yearssince the onset of chorea.The neuropathological study was carried out on forma-lin-fixed sections stained with hematoxylin-eosin, cresylviolet for Nissl substance, Heidenhain-Woelcke for myelin,thioflavine S for amyloid, and silver salts for neurofibrillarychanges (Bodian’s method). Immunohistochemistry wasperformed with antibodies to beta-amyloid (4G8), alpha-synuclein (4D6), ubiquitin (polyclonal), phosphorylated tau(AT8), prion protein (3F4), GFAP (polyclonal), CD3/43,leucocytes common antigen CD45, and MBP (polyclonal).Histopathological examination revealed mild neuronal lossin the cerebral cortex and basal ganglia. Reactive astrogl-iosis and microglia activation were marked in the thalamus,caudate, putamen and substantia nigra (SN) and morepronounced in the brainstem and cerebellum. Slight peri-vascular lymphocytic infiltration was present in the hemi-spheric and cerebellar white matter as well as in thestriatum, thalamus and brainstem. Extracellular deposits orintracellular inclusions were absent but esinophilic, ubiq-uitin-positive inclusions suggestive of Marinesco bodieswere found only in the SN. No clear retrospective corre-lation with imaging data was possible.

Aim: Diabetic foot ulcers are the most common cause of nontraumatic lower extremity amputations in the industrialized world. Tissue-engineering products offer a lower extremity salvage strategy when healing does not proceed according to the standard of care. New allogeneic sheets are available for the management of diabetic leg and foot ulcers. Methods: The endpoints of this case series study regard preliminary outcomes of the application of allogeneic keratinocytes composed of benzyl ester of hyaluronic acid to 16 diabetic foot and leg ulcers in 11 patients with type 2 diabetes mellitus. Results: Between 21 and 70 days after cellular therapy, 6 out of 16 lesions were completely healed, reducing the wound dimension by 70% and improving the wound bed score by 52%. Conclusion: The clinical results of the new allogeneic sheets indicate that allogeneic keratinocytes may represent an effective and safe therapy for diabetic foot and leg ulcers in the multidisciplinary approach to this diabetes-related complication.

Background: Merkel cell carcinoma (MCC) is a rare cutaneous neuroendocrine malignancy that usually grows rapidly at the head and neck. Giant forms at the lower limbs are rarely reported and usually affect patients in the eighth decade or older. Methods: We report the case of a 60-year-old man who presented with a giant MCC on his right thigh. We managed this case by applying the 2012 updated guidelines and reviewed all cases of giant MCC of the lower limbs reported in the literature. Results: At the 4-month follow-up, the patient showed complete remission. Conclusion: Giant forms of MCC are still treated as typical cases of MCC, when these patients show a very poor prognosis. In young and adult people, such as our case, wide surgical excisions, sentinel lymph node biopsy in clinically negative node cases, radiotherapy of the regional drain area, and a strict follow-up should be routinely performed to improve patients' survival.

Lichen striatus (LS) is an uncommon dermatosis that generally affects children. The histopathology of LS often shows a polymorphic epidermal reaction process of variable lichenoid and spongiotic changes having no specific histopathological criteria or simulating other diseases. In the present study, we have evaluated the histopathological features of 41 biopsy specimens and the immunohistochemical aspects of 10 cases of LS. In 50% of the cases, we found histopathological and immunopathological features constantly present and allowing a correct diagnosis. In 9 cases, the histopathology was not specific, and in 10 cases, a clear differentiation from other diseases was not possible. Immunohistochemical study demonstrated a CD3+ T-lymphocytic infiltration in which CD8+ cells surrounded necrotic keratinocytes and intraepidermal vesicles filled with Langerhans cells. These findings seem to corroborate the hypothesis that a somatic mutation of a keratinocytic clone could induce an autoimmune response of the host.