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Abstract: Melanocytic matricoma is a rare benign pilar tumor characterized by matrical differentiation and interspersed dendritic melanocytes. It may show cellular atypia and brisk mitotic activity. Histological characterization of some lesions may be difficult. In addition, because the reported cases are few and have limited follow-up, there is insufficient experience to define outcome-based criteria for malignancy. Some cases of melanocytic matricoma with more prominent atypia have been reported as malignant, but their clinical behavior is uncertain. We present a melanocytic matricoma with interspersed benign dendritic melanocytes, but moderate basaloid atypia, focally brisk mitotic activity, and atypical mitoses. Despite the apparently good delimitation of this tumor, higher magnification revealed a slightly irregular border. However, overt malignant features such as necrosis, frank asymmetry, deep infiltration, and ulceration were not present. This tumor showed a complex aberrant genomic profile with multiple whole chromosomes or chromosomal arms, losses, and duplications. The tumor mutational burden was high. A loss-of-function alteration in CDKN2A and a loss-of-function mutation in TP53 were also present. This unexpected molecular profile contrasts with the relatively bland histology of the tumor and is in line with the difficulties in microscopic differential diagnosis between melanocytic matricoma and an indolent malignant pilomatrical tumor. We suggest that molecular studies and longer follow-up periods may help to further understand and more precisely categorize borderline pilomatrical tumors with melanocytic hyperplasia., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Digital polymerase chain reaction (dPCR) is an emerging technology that enables accurate and sensitive quantification of nucleic acids. Most available dPCR systems have two channel optics, with ad hoc software limited to the analysis of single and duplex assays. Although multiplexing strategies were developed, variable assay designs, dPCR systems, and the analysis of low DNA input data restricted the ability for a universal automated clustering approach. To overcome these issues, we developed dPCR Cluster Predictor (dPCP), an R package and a Shiny app for automated analysis of up to 4-plex dPCR data. dPCP can analyse and visualize data generated by multiple dPCR systems carrying out accurate and fast clustering not influenced by the amount and integrity of input of nucleic acids. With the companion Shiny app, the functionalities of dPCP can be accessed through a web browser., (© The Author(s) 2023. Published by Oxford University Press.)

BRD4 is part of a multiprotein complex involved in loading the cohesin complex onto DNA, a fundamental process required for cohesin-mediated loop extrusion and formation of Topologically Associating Domains. Pathogenic variations in this complex have been associated with a growing number of syndromes, collectively known as cohesinopathies, the most classic being Cornelia de Lange syndrome. However, no cohort study has been conducted to delineate the clinical and molecular spectrum of BRD4-related disorder. We formed an international collaborative study, and collected 14 new patients, including two fetuses. We performed phenotype and genotype analysis, integrated prenatal findings from fetopathological examinations, phenotypes of pediatric patients and adults. We report the first cohort of patients with BRD4-related disorder and delineate the dysmorphic features at different ages. This work extends the phenotypic spectrum of cohesinopathies and characterize a new clinically relevant and recognizable pattern, distinguishable from the other cohesinopathies., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)