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Pancreatic adenosquamous carcinoma (PASC) is a rare pathological subtype of pancreatic cancer (PC), with a worse prognosis than pancreatic ductal adenocarcinoma (PDAC). Due to its rarity, our knowledge of PASC and its biological characteristics are limited. In this review, we provide an overview of the histogenesis, genetic features, diagnosis, treatment, and prognosis of PASC, as well as pancreatic squamous cell carcinoma (PSCC). The information provided here may help to clarify our understanding of PASC and provide useful avenues for further research on this disease. [ABSTRACT FROM AUTHOR]

Pitx2 is a transcription factor responsible for establishment of the right–left axis and development of the gut and pituitary. In mouse embryos, Pitx2 is expressed in the greater curvature of the stomach and midgut. Previously, Pitx2 was studied in pituitary neuroendocrine tumours but not in other NETs. Pitx2 expression was immunohistochemically assessed in whole sections and tissue microarrays in a cohort of 224 neuroendocrine neoplasms, and was analysed in 29 cases. The cohort included 18 cauda equina NETs, 38 paragangliomas, 98 cases of primary visceral NETs from different organs, 23 metastases of visceral NETs and 47 neuroendocrine carcinomas (NECs). Pitx2 expression was observed in 29.5% (29 of 98) NETs and 14.9% (7 of 47) NECs, but was not observed in any paraganglioma or cauda equina NET. Pitx2 was observed only in tumours of midgut‐derived organs, including the small intestine (100%, 20 of 20), appendix (88.9%, eight of nine) and large intestine (9.1%, one of 11 – only caecal NET). The NETs of remaining locations were negative. Pitx2 was 96.7% sensitive and 100% specific for NETs of midgut origin. In NECs, Pitx2 positivity was observed in goblet cell adenocarcinoma (75%, three of four), medullary thyroid carcinoma (42.9, three of seven) and one Merkel cell carcinoma (25%, one of four). In metastatic NETs, Pitx2 was observed in all the tumours originating in the small intestine (n = 17) or caecum (n = 1). No positivity was observed in tumours from other locations (four pancreas, one lung). We observed no correlation between immunoreactivity and mRNA expression. Thus, Pitx2 immunohistochemistry can be helpful in assessing the midgut origin of NETs. [ABSTRACT FROM AUTHOR]

Dermatofibroma (DF) is a mesenchymal tumor of the dermis, but its exact differentiation lineage is still uncertain. A progenitor cell that may be able to differentiate into fibroblastic, myofibroblastic, or fibrohistiocytic cells has been hypothesized. Some authors have also proposed the possibility of a monocytic-histiocytic origin. We stained 47 consecutive dermatofibromas with CD64, CD34, CD14, CD163, and CD68 to test which marker is more reliable for the diagnosis and to gain insight into their histogenesis. From the 35 cases stained with the whole immunohistochemical panel, all were positive for CD64, mostly showing a strong and diffuse pattern. Regarding all the other staining, CD14 was strongly positive in 77% of the lesions and CD163 in 20%. The CD68 stain was intense and diffuse only in 20% of the cases. All lesions were negative for CD34, but two of them showed patchy and weak staining. DFs were immunohistochemically stained positively with a set of macrophage/monocyte/histiocyte lineage markers such as CD14, CD68, CD163, and CD64. This finding favors an active pro-inflammatory immature monocyte-lineage cell as the more suitable origin for DF. CD64 seems to be more sensitive than other markers to confirm the diagnosis. [ABSTRACT FROM AUTHOR]

This study is aimed to identify histological construct development in eye for quail embryo. In this study, we are focused on the tracing appearance of eye from beginning until completion of main structures of the eye at seventh day of incubation. The results shown that there is no structure appear in the optic vesicles at (12 hr) incubator. However, the optic vesicles is began to appear and form the optic cup in the embryo at (24 hr ) incubator . After that appeared in fifth day incubation( lens, retina, optic nerve and corona). However, the iris is not formed yet at that age. However, it is appeared in embryo age at seven the days incubation . Whole embryos were separated for ages 12, 24 and 60 hours incubation for whole mount procedure, while the embryos on the fifth and seventh days were Tissue sectioning was performed at the eye region [ABSTRACT FROM AUTHOR]

Xanthomatous meningioma is an extremely rare subtype of metaplastic meningiomas with few cases reported in the literature. Histopathologically, it is composed of oval-shaped cells that have central nuclei and cytoplasm with lipid-filled vacuoles, resembling macrophages. Here, the authors present a case of xanthomatous meningioma and discuss the hypotheses related to its origin and the differential diagnosis. A 40-year-old woman presented with an increased headache complaint over the past month. A computed tomography scan revealed a heterogeneous mass on the right parietal lobe, following which a right craniotomy was done. Microscopic examination showed neoplastic meningothelial cells with whorl formation and areas of xanthomatous changes. Both meningothelial and xanthomatous cells were positive with vimentin, progesterone, and epithelial membrane antigen. CD68 and lysozyme were expressed only in the xanthomatous component, and there was no expression with periodic acid-Schiff (PAS) stain and PAS–diastase. As the diagnostic criteria of atypical meningioma were not observed, a diagnosis of xanthomatous meningioma, WHO grade I, was made. Owing to the characteristic xanthomatous changes, its differential diagnosis includes grade II clear cell meningioma, Rosai–Dorfman disease, and hemangioblastoma. To avoid misidentifying these cells as macrophages, a high degree of awareness of this unique subtype of meningioma is required.

Introduction: About 5% of the world population is affected from various thyroid disorders. The present study is undertaken to describe the morphological and morphometric variations in the fetal thyroid glands of thyroid at different stages of development in the intrauterine life. Methodology: Forty medically terminated fetuses of both sexes ranging from 15 to 36 weeks of gestation were included. The external parameters recorded were: Fetal weight; crown-rump length; foot Length; Location; Presence/absence of isthmus; Presence of pyramidal lobe; Presence of an accessory thyroid tissue were observed in situ. The length, width, and thickness of each lobe and the isthmus were noted. Results: The specimens were categorized into three gestational groups, i.e., 10–20 weeks, 21–30 weeks, and 31–40 weeks. The statistical analysis suggests that there is significant increase in fetal thyroid weight, lengths and widths of the right and left lobes, and length of the isthmus with increase in gestational age. There was no significant increase in width of isthmus with gestational age. There was no significant difference in all thyroid parameters by gender. Conclusion: The data regarding the various parameters collected and analyzed in the present study emphasized the significance of an insight into the morphological variations, morphometric dimensions, and histological findings of foetal thyroid glands in diagnosing various diseases.

Overall, the immunophenotype of SIs in the transitional area was identical to that of excretory ducts (Supporting information, S1).[[4]] There were approximately 13 excretory duct-, 6 striated duct- and 5 intercalated duct-type SIs in the lymphoid stroma of WT and 12 excretory duct-, 1 striated duct- and 8 intercalated duct-type SIs in the peritumoral lymph node. Intercalated duct- or striated duct-type SIs were minor components of SIs in the lymphoid stroma of WT and a peritumoral lymph node. In summary, the present WT may have an origin from excretory duct-type SIs in the lymphoid stroma, implying that striated ducts are not essential for the histogenesis and morphogenesis of WT. [Extracted from the article]

Epithelial pearls and Keratin pearls are pathognomonic of squamous cell carcinoma. However, their histogenesis is not well understood. Only a handful of studies have been conducted in the past in this regard. This brief communication aims to understand the formation of these pearls with a few of our own experiences. [ABSTRACT FROM AUTHOR]

Mesonephric lesions in the female genital tract are uncommon, with those arising from the upper tract being much less frequent than those developing in the lower tract (mesonephric hyperplasia and carcinoma). The most common upper tract lesions include rete cyst/cystadenoma and female adnexal tumour of Wolffian origin (FATWO). The integration of morphological, immunohistochemical and molecular studies on FATWOs has enabled recognition of a novel entity, the STK11 adnexal tumour, which is often associated with Peutz–Jeghers syndrome (~50%) and frequently has a salivary gland morphology but an unknown origin. Similarly, 'mesonephric‐like' adenocarcinoma, an entity with striking similarities to mesonephric carcinoma but currently favoured to be of Müllerian derivation based on its association with other Müllerian tumours and molecular findings, has also been recently described, and may histologically mimic both FATWOs and STK11 adnexal tumours. In this review, we provide a historical overview of upper female genital tract mesonephric proliferations and discuss mesonephric lesions, STK11 adnexal tumour, mesonephric‐like adenocarcinoma, and mimickers, the most common being endometrioid carcinoma. [ABSTRACT FROM AUTHOR]

Shell suture obliteration (ankylosis) was exceptionally frequent in the earliest turtles, in contrast to post-Triassic taxa. Since modern turtles grow mostly along sutures, early ankylosis in Triassic taxa is intriguing. The Triassic turtle Proterochersis porebensis Szczygielski & Sulej, 2016 is known from numerous specimens, allowing observation of shell microstructure changes during ontogeny. Shell ankylosis occurred seemingly randomly in individuals of variable size, including small and morphologically juvenile, and completely obscured the initial bony composition. We propose that this phenomenon in the Triassic turtles can be an effect of early evolutionary stages of shell histogenesis and physiological mechanisms still used in shell regeneration in modern species. We also describe some parallels between the unusual peripheral microstructure of another Triassic turtle, Waluchelys cavitesta Sterli, Martínez, Cerda & Apaldetti, 2020, and Proterochersis porebensis. Microstructural changes imply that Proterochersis porebensis could change habitat during ontogeny, small individuals appearing more aquatic and larger more terrestrial. [ABSTRACT FROM AUTHOR]

Germ cell tumours (GCTs) are a collection of benign and malignant neoplasms derived from primordial germ cells. They are uniquely able to recapitulate embryonic and extraembryonic tissues, which carries prognostic and therapeutic significance. The developmental pathways underpinning GCT initiation and histogenesis are incompletely understood. Here, we study the relationship of histogenesis and clonal diversification in GCTs by analysing the genomes and transcriptomes of 547 microdissected histological units. We find no correlation between genomic and histological heterogeneity. However, we identify unifying features including the retention of fetal developmental transcripts across tissues, expression changes on chromosome 12p, and a conserved somatic evolutionary sequence of whole genome duplication followed by clonal diversification. While this pattern is preserved across all GCTs, the developmental timing of the duplication varies between prepubertal and postpubertal cases. In addition, tumours of younger children exhibit distinct substitution signatures which may lend themselves as potential biomarkers for risk stratification. Our findings portray the extensive diversification of GCT tissues and genetic subclones as randomly distributed, while identifying overarching transcriptional and genomic features. The molecular characterisation of germ cell tumours (GCT) is necessary to understand their development and histological diversification. Here, the authors use whole-genome and transcriptome sequencing of GCTs across distinct histologies to reveal their somatic evolution and clonal diversification, as well as identify several putative biomarkers for treatment stratification. [ABSTRACT FROM AUTHOR]

Background: Placental hepatic heterotopia is a benign lesion with unclear histogenesis hypothesized to be of hepatocytic differentiation of yolk sac elements. Of the 14 hepatic heterotopia cases previously reported, 12 cases occurred in preterm labor. Case report: A case of intraplacental hepatic heterotopia in a 27-year-old female with pre-term delivery at 31 + 5 weeks gestational age is described. Histopathological examination revealed a well-demarcated lesion with cohesive, monotonous cells and pale to clear cytoplasm. The differential diagnoses of this lesion included benign, primary and metastatic malignant entities. The lesional cells expressed HepPar-1, CAM 5.2, Glypican-3, and AFP, consistent with cells of hepatic origin. Conclusion: Intraplacental hepatic heterotopia is associated with premature labor. Distinguishing this lesion from maternal and fetal malignancies with similar histopathological presentation has important clinical implications in patient care. [ABSTRACT FROM AUTHOR]

Based on light microscopy data, hemocytes of Crenomytilus grayanus were classified into five morphological types common for Bivalvia. In the stage of sexual inertia (late October), the proportions of the cell types are as follows: (1) hemoblasts (0.2 ± 0.1%), (2) hyalinocytes (1.9 ± 0.3%), and also (3) basophilic (10.9 ± 1.4%), (4) neutrophilic (13.3 ± 3.0%), and (5) acidophilic (74.1 ± 2.9%) granulocytes. All hemocytes were divided into four groups on the basis of their size (FSC) and complexity (SSC) by flow cytometry. Correlation analysis has shown that R1 corresponds to hemoblasts, R2 to hyalinocytes, and R4 to granulocytes and their acidophilic forms. However, these correlations are not observed in the summer season. The hemocyte morphology and quantitative relationships between their structural types confirm Mix's hematopoietic model, which postulates histogenetic continuity of hyalinocytes and granulocytes. The arrangement of cells in the light-scatter dot plots (FSC vs. SSC) indicates their maturity stage; it depends on functional status and may change with disturbances of the mitotic cycle. The hemocyte population in C. grayanus shows a low rate of renewal and a dominance of acidophilic granulocytes (up to 99% of all cells in the sexual inertia stage), which suggests a strategy targeted at long-term maintenance of highly differentiated cells and is consistent with the long life expectancy of the species. [ABSTRACT FROM AUTHOR]

Background: Multiple kidney tumours are frequently seen in hereditary syndromes and familial diseases. Renal collision tumours (RCT) are characterized by the simultaneous existence of different and unrelated tumour types within the same location in the kidney, forming a single, heterogenous lesion. RCT are uncommon histological entities with distinctive features. The most frequent subtypes include clear cell renal cell carcinoma (CCRCC), papillary renal cell carcinoma (PRCC), chromophobe renal cell carcinoma (CRCC), and collecting duct carcinoma (CDC).Case Presentation: Here, we report three sporadic cases of RCT successfully treated by nephrectomy and confirmed by histological analysis. The first case was of a 64-year-old man diagnosed with RCT composed of a stage 2 nucleolar grade 3 CCRCC and a stage 1a nucleolar grade 2 type 1 PRCC. The second case was of a 68-year-old woman diagnosed with a combined nucleolar grade 2 type 1 PRCC and an angiomyolipoma (non-assessed stage), while the third case was of a 59-year-old woman diagnosed with a combined stage 1a nucleolar grade 3 CCRCC and a stage 1b CDC.Conclusions: Due to the rarity of RCT, there are no standard guidelines for their management. Hence, the prognosis is considered to be associated with the most aggressive component, possibly the tumour with the highest nucleolar grade and stage. The histogenesis of RCT remains debated, and increase in knowledge regarding this can help enable the development of targeted therapies for advanced or metastatic tumours. [ABSTRACT FROM AUTHOR]

Objectives: In this study, we aimed to investigate the changes in testicular histogenesis in bisphenol-a exposed rats by ascorbic acid during prenatal and early postnatal life. Materials and Methods: Eight weeks old 15 pregnant rats were divided into 3 groups, each containing 5 rats. Pups were delivered by spontaneous vaginal delivery. Group A had 15 male rat pups, from 5 pregnant female rats, which were fed on a standard diet during pregnancy and lactation till day 21. Group B had 15 male rat pups from 5 pregnant female rats which were given 250 µg/kg/day of Bisphenol A subcutaneously during pregnancy and lactation till day 21. Group C had 15 male rat pups from 5 pregnant female rats which were given 250 µg/kg/day of Bisphenol A subcutaneously and 150 mg/kg/day of ascorbic acid orally during pregnancy and lactation till day 21. Results: In group B, 86.6% of rats had irregular seminiferous tubules. This irregularity was reduced to 26.6% in group C. The basement membranes of tubules were irregular along with a detachment of germinal epithelium in 80% of rats in group B which reduced to 26.6% in group C. The cell debris was present in 80% of tubular lumina in group B rats with only 13.3% in group C. These parameters were improved with ascorbic acid in group C with a significant p-value. Conclusion: Biphenol A adversely affects the histogenesis of testes by causing oxidative stress when given during pregnancy and lactation and ascorbic acid improves BPA exposure to developing testes and may preserve spermatogenesis and male fertility. [ABSTRACT FROM AUTHOR]

The odontogenic keratocyst (OKC), which makes up approximately 10% of odontogenic cysts, is a locally-aggressive cystic lesion that affects the maxilla or the mandible and is capable of causing major destruction. OKCs have been a topic of debate ever since they were discovered and named. The origin of OKC is still debatable, the OKC mostly occur intraosseusly and is thought to be derived from odontogenic epithelium as the dental lamina and its remnants after the organ has served its purpose. The WHO had classified OKC under 'developmental odontogenic cysts of jaw' in the 1971 and 1992 classifications . Nevertheless, the 2005 WHO classification controversially considered OKC an odontogenic neoplasm and gave it the name 'keratocystic odontogenic tumor' (KCOT) . The reasons for this change were the lesion's high recurrence rate, aggressive clinical behavior, association with nevoid basal cell carcinoma syndrome and mutations in the PTCH tumor suppressor gene. The designation of OKC changed once again in the 2017 WHO classification, reverting back to the more accepted term 'odontogenic keratocyst'. OKCs grow in an antero-posterior direction, infiltrating the cancellous bone of the jaws, often without obvious bone expansion, so it is commonly asymptomatic despite its aggressive nature. The presence of multiple OKCs is especially correlated to nevoid basal cell carcinoma syndrome (NBCCS), also known as Gorlin-Goltz syndrome, the radiographic appearance of OKC ranges from well-defined unilocular lesions to extensive multilocular lesions with ill-defined borders. This review will cover the history of this lesion's classification, nomenclature, as well as its histogenesis, clinical presentation, histopathology, radiography, genetics, treatment, prognosis and complications. [ABSTRACT FROM AUTHOR]

Sarcomatoid carcinoma of the pancreas (SCP) is a rare and aggressive subtype of undifferentiated pancreatic ductal adenocarcinoma, with a generally poor prognosis and only sporadic cases reported worldwide. Histologically, the most notable feature of SCP is the presence of abundant of mesenchymatoid spindle tumor cells in the tumor, which lack glandular differentiation. Immunohistochemically, SCP is characterized by the expression of both mesenchymal and epithelial markers. With only a few reported cases, there is limited knowledge about its molecular and clinicopathological characteristics. Therefore, the present study performed a literature search to identify all relevant published studies. The present review provides an overview of the histogenesis, diagnosis, genetic features, prognosis and treatment of SCP, specifically focusing on the molecular alterations. Furthermore, a single-center experience is reported, which adds to the limited evidence available in the literature. [ABSTRACT FROM AUTHOR]

In this work we present a detailed study of the major events during retinal histogenesis of the cuttlefish Sepia officinalis from early embryos to newly hatched animals and juveniles. For this purpose , we carried out morphometric and histological analyses using light and scanning electron microscopy. From St19, the first embryonic stage analysed, to St23/24 the embryonic retina is composed of a pseudostratified epithelium showing abundant mitotic figures in the more internal surface. At St24 the first photoreceptor nuclei appear in the presumptive inner segment layer, while an incipient layer of apical processes of the future rhabdomeric layer become visible at St25. From this stage onwards, both the rhabdomeric layer and the inner segment layer increase in size until postnatal ages. In contrast, the width of the supporting cell layer progressively decreases from St25/26 until postnatal ages. S. officinalis embryos hatched in a morphologically advanced state, showing a differentiated retina even in the last stages of the embryonic period. However, features of immaturity are still observable in the retinal tissue during the first postnatal weeks of life, such as the existence of mitotic figures in the apical region of the supporting cell layer and migrating nuclei of differentiating photoreceptors crossing the basal membrane to reach their final location in the inner segment layer. Therefore, postnatal retinal neurogenesis is present in juvenile specimens of S. officinalis. • The genesis and differentiation of photoreceptors occur during the period of organogenesis. • Photoreceptor progenitor cells originate in the supporting cell layer during development. • The supporting cell layer maintains the homeostasis and retinal tissue growth in juvenile individuals. • Retinal neurogenesis is present in the juvenile cutlefish. • The cutlefish retina may constitute a useful model system for studying cell differentiation and tissue regeneration. [ABSTRACT FROM AUTHOR]

Adenomatoid Odontogenic Tumor (AOT) accounts for 3 % of all odontogenic tumors. It has been classified by WHO as an odontogenic tumor of purely epithelial origin. The current study attempts to establish the origin of the tumor along with detailed histopathological and clinicoradiographic analysis of 43 cases of AOT. Forty-three cases were reviewed from the departmental archives for demographic data, radiographic features and histological features. Further, histopathological slides were stained with Picrosirius Red (PSR) and observed under polarised light. A majority of the cases were seen in the anterior jaws (76.7 %), and were less than 3 cms (76.7 %) in greatest dimension. Equal number of cases were of follicular and extra-follicular location while one was peripheral. Predominantly solid histological pattern was noted in 53.5 %. Varied sub-patterns were observed with most cases exhibiting solid nodules and strands of tumor cells. Few cases showed melanin pigmentation. Over a third of cases (37.2 %) showed dentigerous cyst like areas and one case each showed features of ossifying fibroma and focal cemento-osseous dysplasia. Tumor droplets, hyaline rings within duct-like structures, dentinoid material and osteodentin showed reddish yellow birefringence when observed under polarised microscopy post PSR staining. This study highlights the diverse histopathological variation of AOT with evidence to reclassify it as a mixed odontogenic tumor based on the polarising microscopic findings with PSR staining. • Picrosirius red staining along with polarised microscopy has been used to highlight the mesenchymal component within AOT. • The study challenges conventional understanding of AOT by proposing a mixed odontogenic origin. • A detailed clinical, radiographic and pathologic analysis has been done, aiding in better understanding of the topic. [ABSTRACT FROM AUTHOR]

The pretectum has a distinct nuclear arrangement and complex neurochemical anatomy. While previous genoarchitectural studies have described rostrocaudal and dorsoventral progenitor domains and subdomains in different species, the relationship between these early partitions and its later derivatives in the mature anatomy is less understood. The signals and transcription factors that control the establishment of pretectal anatomy are practically unknown. We investigated the possibility that some aspects of the development of pretectal divisions are controlled by Wnt signaling, focusing on the transitional stage between neurogenesis and histogenesis in zebrafish. Using several molecular markers and following the prosomeric model, we identified derivatives from each rostrocaudal pretectal progenitor domain and described the localization of gad1b -positive GABAergic and vglut2.2 -positive glutamatergic cell clusters. We also attempted to relate these clusters to pretectal nuclei in the mature brain. Then, we examined the influence of Wnt signaling on the size of neurochemically distinctive pretectal areas, using a chemical inhibitor of the Wnt pathway and the CRISPR/Cas9 approach to knock out genes that encode the Wnt pathway mediators, Lef1 and Tcf7l2. The downregulation of the Wnt pathway led to a decrease in two GABAergic clusters and an expansion of a glutamatergic subregion in the maturing pretectum. This revealed an instructive role of the Wnt signal in the development of the pretectum during neurogenesis. The molecular anatomy presented here improves our understanding of pretectal development during early postmitotic stages and support the hypothesis that Wnt signaling is involved in shaping the neurochemical organization of the pretectum. [ABSTRACT FROM AUTHOR]

The morphological spectrum of primary ovarian mucinous and seromucinous tumours is broad, and presents an array of diagnostic challenges, many unique to these tumour types. This reflects the heterogeneous nature of these lesions, their varied histogenesis and evolving classification systems over recent decades, with further modification to the seromucinous category incorporated in the recently published 5th edition of the World Health Organisation (WHO) Classification of female genital tumours. In this review we provide an update on the classification of these neoplasms and discuss their histogenesis and diverse morphology, focusing on areas which are diagnostically problematic. We also cover tumour grading, differential diagnosis, immunohistochemistry, the recent elucidation of the molecular underpinnings of ovarian mucinous neoplasia and discuss the gross and intra-operative handling of these tumours. A number of diagnostic issues remain unresolved, highlighting the importance of further research on this front, as well as a multidisciplinary approach in the care of patients with ovarian mucinous and seromucinous neoplasia. [ABSTRACT FROM AUTHOR]

Calcifying pseudoneoplasm of neuroaxis (CAPNON) is a rare lesion of the central nervous system with uncertain histogenesis. We further explored phenotypic spectrum of the entity with respect to possible histogenesis. We collected 5 cases of CAPNONs, performed a detailed morphological assessment, and performed an extensive immunohistochemical analysis (EMA, progesterone receptors, MUC4, SSTR2A, cytokeratin AE1/3, cytokeratin 18, GFAP, neurofilaments, desmin, nestin, synaptophysin, S100 protein, SOX10, CD56, Podoplanin, SATB2, ERG, CD45, and CD163) to elucidate the histogenesis. Furthermore, we performed NGS analysis of one case. The clinical course was benign in all cases. All lesions showed extensively calcified matrix in multilobular arrangement, with a palisade of osteoblast-like cells. Characteristic fibrohyaline matrix was notable in 4/5 cases, while one case was myxoid with rod-like calcifications. Metaplastic lamellar bone was present in 4/5 cases and psammoma bodies were present in 2/5 cases. In 4/5 cases, areas of entrapped glial tissue were present. Expression of EMA was focally present in 3/5 cases, SSTR2A and nestin in 2/5 cases, and progesterone receptor in 2/5 cases in rare cells. We did not observe concomitant expression of EMA, SSTR2A, and progesterone receptor in the same cellular subsets. In one case, NGS showed multiple chromosomal alterations and missense mutation in PIK3CA, attributable to the admixed meningothelial population compatible with meningioma. In another case, biphasic proliferation with myoepithelial phenotype was present. The lesions showed no lineage-specific immunoprofile. Additional pathology was identified in two cases, furthermore suggestive of a possible reactive origin of the lesion. [ABSTRACT FROM AUTHOR]

Though the anatomy and physiology of the adult caprine (Capra hircus L.) stomach have been investigated extensively, the early development of the abomasum has not yet been fully elucidated. The glandular part of abomasum plays an important role in digestion of ingested food by action of gastric juices. Very few studies have been conducted so far regarding histogenesis of goat foetal abomasum in India. In the present study, we have investigated the embryonic and early foetal development of the goat, Capra hircus L. fundic abomasum. We collected 36 developing abomasum of healthy and normal embryos/foeti of goat and assigned them into three group viz. Gr. I (0-50 days of gestation), Gr. II (51-100 days of gestation) and Gr. III (101-150 days of gestation). Small pieces of tissues were processed by routine paraffin. The wall of glandular stomach, the fundic part, was composed of epithelium, pleuripotent blastemic tissue and serosa up to 44 days of gestation. Tunica muscularis became separable at 46 days of gestation. The epithelium was stratified type up to 50 days and gradually changed to pseudo-stratified columnar to simple columnar type from 76 days of gestation. Primary and secondary abomasal folds were observed at 51 and 76 days of gestation, respectively. Gastric pit, the fore runner of gastric gland was reported first at 70 days. The gland became branched tubular type at 145 days. The cells found in the mucosa of the abomasum were surface epithelial cells, chief cells, parietal cells, mucous neck cells and undifferentiated cells. Chief and parietal cell were observed at 76 days and mucous neck cells at 82 days of gestation. Reticular, collagen and elastic fibers came into sight at 38, 76 and 100 days of gestation, respectively. The present study is expected to supplement known data and knowledge regarding histogenesis of goat fetal abomasum and help in diagnosis and treatment of related congenital anomalies. [ABSTRACT FROM AUTHOR]

Germ cell tumors (GCTs) originate during the histogenesis of primordial germ cells to mature gametes. Previous studies identified five histogenic mechanisms in ovarian mature teratomas (type I: failure of meiosis I; type II: failure of meiosis II; type III: duplication of the genome of a mature gamete; type IV: no meiosis; and type V: fusion of two different ova), but those of other GCTs remain elusive. In this study, we analyzed 84 GCTs of various pathologic types to identify the histogenesis using single‐nucleotide polymorphism array by analyzing copy‐neutral loss of heterozygosity (CN‐LOH) and copy number alterations (CNAs). We detected types I and II in ovarian teratomas, type III in ovarian teratomas and yolk sac tumors (YSTs), and type IV in all GCT types. The GCTs with multiple‐type histogenesis (I–IV) (ovarian mature/immature teratomas and YST) show meiotic CN‐LOH with scant CNAs. Type IV‐only GCTs are either with mitotic CN‐LOH and abundant CNAs (seminoma, dysgerminoma, testicular mixed GCTs) or with scant CNAs and no CN‐LOH (pediatric testicular and mediastinal teratomas). The development sequences of CN‐LOH and CNA are different between the multiple type (I–IV) GCTs and type IV‐only GCTs. We analyzed two different histologic areas in eight GCTs (one mature teratoma with a mucin‐secreting adenoma, two immature teratomas, and five mixed GCTs). We found that GCTs (mature teratoma, immature teratoma, and mixed GCT) showed different genomic alterations between histologic areas, suggesting that genomic differences within a GCT could accompany histologic differentiation. Of note, we found evidence for collision tumors in a mixed GCT. Our data indicate that GCTs may have various histogenesis and intratumoral genomic differences, which might provide important information for the identification of GCTs, especially for those with different histologic areas. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Brain development is regulated by conserved transcriptional programs across species, but little is known about the divergent mechanisms that create species- specific characteristics. Among brain regions, human cerebellar histogenesis differs in complexity compared with nonhuman primates and rodents, making it important to develop methods to generate human cerebellar neurons that closely resemble those in the developing human cerebellum. We report a rapid protocol for the derivation of the human ATOH1 lineage, the precursor of excitatory cerebellar neurons, from human pluripotent stem cells (hPSCs). Upon transplantation into juvenile mice, hPSCderived cerebellar granule cells migrated along glial fibers and integrated into the cerebellar cortex. By Translational Ribosome Affinity Purification- seq, we identified an unexpected temporal shift in the expression of RBFOX3 (NeuN) and NEUROD1, which are classically associated with differentiated neurons, in the human outer external granule layer. This molecular divergence may enable the protracted development of the human cerebellum compared to mice. [ABSTRACT FROM AUTHOR]

A triangular lingual prominence (LP) is a characteristic part of the tongue in Anseriformes containing adipose tissue. The parakeratinized epithelium (PEp) covers the LP. Studies aimed to describe the histogenesis of PEp during the process of the intensive formation of the LP in domestic goose during embryonic period and to determine the structural readiness to perform a protective function. The study were conducted by using LM, SEM and TEM technique. The results revealed that on day 16th the undifferentiated epithelium of LP transformed into the typical avian multilayered epithelium. Contrary to pattern of histogenesis of parakeratinized epithelium on the lingual body, on the medial and lateral areas of the elongating and bulging LP were formed epithelial furrows. Which around 20th day, on lateral areas of LP deepened up to half of epithelium, whereas on the medial area began to fade. The ultrastructure of cells lying in furrows indicated progressive apoptosis-like degeneration. On the 25th day, shallow furrows were only present on lateral areas, where bulging of LP was continued. Whereas the epithelium on medial area started cornification by the accumulation of cytokeratin fibers. Lack of the periderm during the development of the PEp of the LP indicated its endodermal origin. [ABSTRACT FROM AUTHOR]

The purinergic signaling system (PSS) occupies an exceptional position in the regulation of cellular processes, maintaining the homeostasis of the retina of vertebrates. In addition to general regularities, taxon-specific differences, genetically and metabolically determined, are manifested in the functioning of PSS in the retina. Signal cascades with the participation of PSS components can perform a dual role in the retina: they have both a damaging and protective effect, which is largely determined by the conditions of the cellular microenvironment and the molecular context. The identification of key components in the functioning of the PSS, linking it with other endogenous regulatory systems, creates prerequisites for the selection of cellular and molecular targets for neuroprotection in human retinal pathologies. [ABSTRACT FROM AUTHOR]

Primary breast osteosarcoma (PBOS) is an extremely rare and poor prognostic malignancy that has not a definitive treatment guideline. Here, we presented a successfully treated case of PBOS and provided a comprehensive review of the literature which revealed the divergence of opinions regarding the histogenesis and management of this malignancy [ABSTRACT FROM AUTHOR]

In investigating fetal organ development, fetus of the rabbit was one of the furthermost frequently handled as a model in animal investigational research. During the second half of gestation in rabbit fetusesthorax volume (TV) was the predictive factor for assessment of normal development. Concerning these fetuses, evaluation of lung development was more applicable in the 20th–29th gestational days for experiments. A large internal surface area in which the inspired air and capillary blood got in close contact to each other was specified by the lung tissue. Consequently, an efficient gas exchange was occurred. A cycle of separate but overlapping developmental processes happened to reach this target. The anlage of the left and right lungs appeared as an outpouching of the foregut endoderm during organogenesis. A repetitive process of outgrowth and branching pattern (branching morphogenesis) was occurred in each lung bud. Consequently, all of the future airways were formed mainly during the pseudoglandular stage. Repetitive airspace septation would lead to tremendous increase of the gas exchange surface area in both late fetal and postnatal lung development leading to the formation of alveoli. The first air-blood barriers were appeared and surfactant production began during the canalicular stage. [ABSTRACT FROM AUTHOR]

Islet-like clusters derived from human embryonic stem cells (hESC) hold the potential to cure type 1 diabetes mellitus. Differentiation protocols of islet-like clusters lead to the generation of minor fractions of nonendocrine cells, which are mainly from endodermal and mesodermal lineages, and the risk of implanting these is unclear. In the present study, the histogenesis and the tumorigenicity of nonendocrine cells were investigated in vivo. Immunodeficient mice were implanted under the kidney capsule with islet-like clusters which were derived from differentiation of cells batches with either an intermediate or poor cell purity and followed for 8 or 26 weeks. Using immunohistochemistry and other techniques, it was found that the intermediate differentiated cell implants had limited numbers of small duct-like cysts and nonpancreatic tissue resembling gastrointestinal and retinal pigmented epithelium. In contrast, highly proliferative cystic teratomas were found at a high incidence at the implant site after 8 weeks, only in the animals implanted with the poorly differentiated cells. These findings indicate that the risk for teratoma formation and the amount of nonpancreatic tissue can be minimized by careful in-process characterization of the cells and thus highlights the importance of high purity at transplantation and a thorough ex-vivo characterization during cell product development. [ABSTRACT FROM AUTHOR]

Splenic stromal sarcomas are rarely reported tumours that were previously grouped as non-angiomatous, non-lymphomatous mesenchymal neoplasms of the canine spleen. Highly variable survival times have been reported probably due to their heterogeneous nature. The purpose of this study was to assess the outcome and prognostic factors in dogs with splenic stromal sarcoma after treatment by splenectomy. Clinical data were collected retrospectively and histopathology was reviewed for 47 patients. Histological classification, based on morphology in haematoxylin and eosin-stained sections, in conjunction with immunolabelling of macrophage scavenger receptor-A (CD204), desmin, factor VIII-related antigen and smooth muscle actin ,yielded diagnoses of undifferentiated stromal sarcoma (n = 22), complex nodular hyperplasia (CNH, n = 9), sarcoma arising from benign complex nodular hyperplasia (n = 3), histiocytic sarcoma (n = 3), haemangiosarcoma (n = 1) and leiomyosarcoma (n = 1). Four samples were excluded from analysis due to extensive necrosis. An anti-podoplanin (PDPN) antibody was validated on canine tissue and used to assess expression of this protein as a potential indicator of the tissue of origin of the neoplasms (28/42 tumours were positive). There was a statistically significant difference in survival time between patients with stromal sarcoma (sarcoma from benign CNH and undifferentiated stromal sarcoma) and CNH (178 d versus 637 d, respectively; P = 0.027). Dogs with stromal sarcomas and high mitotic count (≥9 per 10 high-power fields) had a significantly shorter survival time (67 d versus 439 d; P = 0.01). Clinical diagnosis of splenic tumours should include evaluation for the presence of benign nodular hyperplasia morphology and immunohistochemistry to exclude more aggressive malignancies where adjuvant therapy is recommended. As in humans, PDPN may be an effective marker for stromal sarcomas of the canine spleen and immunopositivity suggests a fibroblastic reticular or follicular dendritic cell origin. [ABSTRACT FROM AUTHOR]

The defect in the shape of the cervix called "disruption" is caused by an extrinsic action, which, from an embryological point of view, interferes with the normal initial development of the uterus. Dysplasia occurs as a defect in histogenesis, usually due to the action of teratogenic factors. In the presented clinical case, we are discussing about the disorganization of an organ part, in which the uterine fundus and the uterine body are normal and the cervix and isthmus of the uterine body, respectively their left edge is transformed into a thin and elastic cystic wall, thus changing the morphophysiology of the local structure. In addition to the above-mentioned pathology, the patient also presented with incomplete longitudinal vaginal septum. All these determined, in addition to the morphological changes, a clinical symptomatology, related to complex sexual dysfunction. The presence of a paravaginal cyst in the left side of the cervix and uterine isthmus, formed by the effect of tissue disorganization during organogenesis, is not included in the types of congenital uterine abnormalities presented in the literature as utero-vaginal malformations that, according to Berek and Novak, occur in 0.16% of women. [ABSTRACT FROM AUTHOR]

Based on light microscopy investigation of fruits and seeds in Gladiolus imbricatus and Iris sibirica, new data on morphogenesis and histogenesis of the pericarp and seed coat development have been revealed. The inner ovary structure, vascular system and fruit dehiscence were also studied. The ovary of the studied species has trilocular basal part and unilocular upper part with incomplete septae. The vascular system in both species is composed of three dorsal veins and three septal veins. The dorsal veins are each divided into three vascular bundles radially whereas the septal veins are also each divided into three bundles but tangentially. Vascular supply of ovules is provided by septal veins in the central column. In both species, the floral tube falls down with adnate stamens and style at the beginning of fruit ripening. For both species, a dorsiventral (valvate) type of fruit dehiscence is characteristic; however, in I. sibirica, a dorsal (fissuricidal) type, in which valvae are connected at the center, top and base of the capsule, occurs as well. According to our data, capsule in both species belongs to the Lilium-type, with lignified endocarpium. In G. imbricatus, we observed early tissues differentiation in the pericarp as well as earlier and faster dorsal slits formation. The seed coat in G. imbricatus is of endotestal type, while in I. sibirica – of exotestal type. Highly specialized features of the seed coat in G. imbricatus are the following: wing formation by outer integument, few-layered mesotesta and destruction of cellular structure of the inner integument. The obtained data complement our previously suggested consideration about more pronounced morphological adaptations for dissemination of fruits and seeds in G. imbricatus. In this article, we confirm the high level of adaptiveness of fruits and seeds in the anatomy and histogenesis of the pericarp and seed coat in G. imbricatus to external conditions.

Introduction. Nowadays, the incidence of ovarian tumors has increased from 6.0-11.0 % to 19.0-25.0 %, becoming the serious medical, economic and social problem, as they affect the reproductive potential, respectively, demographic situation in the country and future women’s health. Besides this, the majority of them have a tendency to become malignant. Also they are one of the causes of high mortality among the female population. Thus, determination of the main risk factors, knowledge of etiological causes and substantial understanding of pathogenic mechanisms of ovarian tumor will enable to conduct prophylaxis of this disease development and improve the medical aid. The aim of the study. To review and summarize the published investigations devoted to the problems of etiology and pathogenesis of different ovarian tumors according to their histological structure. Materials and methods. The content analysis, method of systemic and comparative analysis, bibliosemantic method of studying the actual scientific researches concerning the etiology and pathogenesis of ovarian tumors, differing by the histological structure and the course specificity, were conducted. The data was searched in scientometric databases: PubMed-NCBI, Medline, Research Gate, Cochrane Database of Systematic Reviews by such keywords: “etiology”, “pathogenesis”, “hypothesis”, “ovarian benign tumor”, “ovarian cancer”, “risk factor”, “histogenesis”, “genetic mutations”, “World Health Organization”, “FIGO” (fr. – Fédération Internationale de Gynécologie et d’Obstétrique). Totally, 84 English, Ukrainian and Russian sources were analyzed. Results. Analysis of modern literature shows that the process of tumor cell transformation has not been fully understood due to their histological features. Nowadays, the numerous endogenous and exogenous risk factors have been identified. And, recently, the traditional theory of the appearance of ovarian tumors has undergone the significant changes. Also, several hypotheses have been proposed to explain the epidemiological factors: the continuous ovulation hypothesis, the hypothesis of gonadotropins excessive secretion, the genetic theory, theory of microenvironment and genetic polymorphism. In recent years, the large number of studies are devoted to the study of the immune system state, the process of apoptosis, morphological and molecular cytogenetics. Conclusions. Thus, according to epidemiological investigations, neoplasms of the ovaries can be regarded as systemic diseases, which occurs on a molecular genetic level with involvement of various endogenous and exogenous factors. However, despite the significant advancements in fundamental science, the causes of tumor appearance and, respectively, the issue of early diagnosis and prophylaxis of the most common neoplasms of the ovaries need further investigations.

Pancreatic adenosquamous carcinoma (PASC) is a rare pathological subtype of pancreatic cancer (PC), with a worse prognosis than pancreatic ductal adenocarcinoma (PDAC). Due to its rarity, our knowledge of PASC and its biological characteristics are limited. In this review, we provide an overview of the histogenesis, genetic features, diagnosis, treatment, and prognosis of PASC, as well as pancreatic squamous cell carcinoma (PSCC). The information provided here may help to clarify our understanding of PASC and provide useful avenues for further research on this disease.

Dermal nonneural granular cell tumor is a rare neoplasm of uncertain histogenesis that Le Boit and colleagues originally described in 1991. It arises commonly from the back, extremities and head and neck. To the best of our knowledge, only 50 cases have been reported in adults in the English literature. A 42-year-old man presented with a polypoid skin nodule of the front side of the chest wall, measuring 1,8 × 1,5 cm. The lesion was removed completely with tumor-free margins. Microscopically, the tumor was composed of a diffuse infiltrate of polygonal cells, S 100 negatives, with abundant granular cytoplasm and vesicular nuclei. The diagnosis of dermal nonneural granular cell tumor was retained. No recurrence was noted during follow up of 6 months. The prognosis is good. [ABSTRACT FROM AUTHOR]

Aims. Mucinous cystic neoplasms (MCNs) are cystic neoplasms with mucinous epithelium surrounded by ovarian-like stroma. Extraovarian MCN occurring in the liver and pancreas have been well characterized. However, only rare case reports of MCN arising outside of these locations have been reported. MCNs arising in unusual locations should enter the differential diagnosis of mucinous intra-abdominal tumors and must be distinguished from more common mimics. Therefore, we aimed to examine a series of MCNs of the retroperitoneum and mesentery to characterize the clinicopathologic features of this entity. Methods and results. Seven MCNs arising in the abdominal mesentery or retroperitoneum were retrospectively identified. A clinicopathologic, histologic, and immunohistochemical (keratin 7, keratin 19, keratin 20, calretinin, inhibin-α, steroidogenic factor-1 (SF-1), estrogen receptor (ER), progesterone receptor (PR), PAX8, CDX2, and CD10) analysis was performed. All 7 MCNs were from females with a median age of 41 years old and a median size of 8 cm. All cases demonstrated mucinous with or without concomitant non-mucinous epithelium overlying spindle cell ovarian-like stroma. Luteinized cells were noted. The epithelium was positive for keratin 7 and keratin 19 in all 7 cases, while the stroma expressed ER, PR, and SF-1 in all cases stained. Calretinin was focally positive in the stroma of 3 of 7 cases, while inhibin-α was focally expressed in 5 of 6 cases. Conclusions. These results highlight the clinicopathologic, histologic, and immunophenotypic similarities between MCNs of the mesentery, retroperitoneum, pancreas, and liver. Overlapping features suggest a common histogenesis for all MCNs, which could include periductal fetal mesenchyme, aberrant migration of primordial germ cells, or abnormal differentiation or metaplasia of the embryonic coelomic epithelium. [ABSTRACT FROM AUTHOR]

Typical carcinoids (TC), atypical carcinoids (AC), large cell neuroendocrine carcinomas (LCNEC), and small cell lung carcinomas (SCLC) encompass a bimodal spectrum of metastatic tumors with morphological, histological and histogenesis differences, The hierarchical structure reveals high cohesiveness between neoplastic cells by mechanical desmosomes barrier assembly in carcinoid tumors and LCNEC, while SCLC does not present an organoid arrangement in morphology, the neoplastic cells are less cohesive. However, the molecular mechanisms that lead to PNENs metastasis remain largely unknown and require further study. In this work, epithelial to mesenchymal transition (EMT) transcription factors were evaluated using a set of twenty-four patients with surgically resected PNENs, including carcinomas. Twelve EMT transcription factors (BMP1 , BMP7 , CALD1 , CDH1 , COL3A1 , COL5A2 , EGFR , ERBB3 , PLEK2 , SNAI2 , STEAP1 , and TCF4) proved to be highly expressed among carcinomas and downregulated in carcinoid tumors, whereas upregulation of BMP1 , CDH2 , KRT14 and downregulation of CAV2 , DSC2 , IL1RN occurred in both histological subtypes. These EMT transcription factors identified were involved in proliferative signals, epithelium desmosomes assembly, and cell motility sequential steps that support PNENs invasion and metastasis in localized surgically resected primary tumor. We used a two-stage design where we first examined the candidate EMT transcription factors using a whole-genome screen, and subsequently, confirmed EMT-like changes by transmission electron microscopy and then, the EMT-related genes that were differentially expressed among PNENs subtypes were predicted through a Metascape analysis by in silico approach. A high expression of these EMT transcription factors was significantly associated with lymph node and distant metastasis. The sequential steps for invasion and metastasis were completed by an inverse association between functional barrier created by PD-L1 immunosuppressive molecule and EMT transcriptional factors. Our study implicates upregulation of EMT transcription factors to high proliferation rates, mechanical molecular barriers disassembly and increased cancer cell motility, as a critical molecular event leading to metastasis risk in PNENs thus emerging as a promising tool to select and customize therapy. [ABSTRACT FROM AUTHOR]

Background and Objectives: Urethral adenocarcinoma is a rare disease with poor prognosis that can display multiple histologic patterns and has an unclear histogenesis. Radical surgery with extensive periurethral resection is the preferred therapeutic approach. Both chemotherapy and radiotherapy have been used as complementary treatment options. Due to the tendency of these tumors to recur, treatment-associated complications, and the limited choice of therapeutic options, patient management can be difficult. Given the lack of literature regarding immunotherapy in urethral adenocarcinoma, our objective was to explore the expression of programmed death receptor-ligand 1 (PD-L1) throughout the different histological subtypes of primary urethral adenocarcinoma. Methods: We reviewed all primary urethral adenocarcinomas diagnosed at our hospital between 1965 and 2019, performed immunohistochemical assays on the tissue blocks, classified them according to their histology and origin, and performed PD-L1 (22C3) immunohistochemistry assays in all cases. Results: We found a total of 5 cases of primary urethral adenocarcinoma. All of the patients were women. One of the cases was a cribriform adenocarcinoma, 2 were columnar-mucinous adenocarcinomas, and 2 were clear cell adenocarcinomas. One of the clear cell adenocarcinomas strongly expressed PD-L1. In addition, a profuse inflammatory infiltration constituted by CD3-positive and CD8-positive T lymphocytes within tumor cells was observed in this case. None of the other cases showed PD-L1 expression. Conclusions: In conclusion, some urethral adenocarcinomas may strongly express PD-L1 and thus could potentially allow the use of immunotherapy in selected cases of advanced or recurrent adenocarcinoma. [ABSTRACT FROM AUTHOR]

Purpose: Branchial cleft anomalies (BCAs) are developmental malformations of the head and neck region. Their histogenesis has been the subject of controversy and is not fully understood. This study aimed to test all present developmental theories ("branchial apparatus," "precervical sinus," "thymopharyngeal," and "inclusion" theories) on a sample of 48 BCAs from a single institution. Methods: We performed a retrospective analysis of clinical–epidemiological and anatomical–pathological characteristics of BCAs treated over a 12-year period in our hospital. Results: Overall, 46 patients (24 [52.17%] women and 22 men [47.83%]) underwent surgical excision of 48 BCAs. The mean patient age at presentation was 31.65 ± 19.40 years. Branchial cleft cysts were found in 42 (87.50%) cases, and branchial cleft sinuses were found in six (12.50%) cases. Eight (16.67%) BCAs were distributed in the preauricular region, 34 (70.83%) at the anterior border of the sternocleidomastoid muscle (SCM), three (6.25%) at the posterior border of the SCM, two (4.17%) in the suprasternal notch, and one (2.08%) in the retrosternal space. Histopathologically, 39 (81.25%) BCAs had a lymphoepithelial structure and nine (18.75%) BCAs had solitary epithelial cells. Inflammation and infection were observed in 24 (50%) and 12 (25%) cases, respectively. Conclusion: None of the hypothesized developmental theories fully explain the embryonic origin of BCA in our study sample. A possible explanation of BCA histogenesis is through the hybrid "branchial inclusion" theory. [ABSTRACT FROM AUTHOR]

Background/Aim: Recent studies suggest that not only the nephrogenic blastema but also the ureteric bud is involved in oncogenesis of Wilms' tumor (WT). However, the occurrence of ureteric bud (UB) derivatives in nephrogenic rest is not yet known. The aim of our study was to find UB derivatives in WT. Materials and Methods: Keratin 17 (KRT17) is expressed exclusively in UB in foetal kidneys. In this study KRT17 immunohistochemistry was used to detect UB-derivatives in 21 triphasic, 2 stromal and 3 epithelial predominant WTs and 9 nephrogenic rests. Results: We have detected KRT17 positive tubular structures resembling UB in 3 of 9 nephrogenic rests and 15 of 26 WTs. Conclusion: Not only the metanephric blastema but also the UB is involved in the histogenesis of nephrogenic rest and WT. [ABSTRACT FROM AUTHOR]

Radial neuronal migration is a key neurodevelopmental event indispensable for proper cortical laminar organization. Cortical neurons mainly use glial fiber guides, cell adhesion dynamics, and cytoskeletal remodeling, among other discrete processes, to radially trek from their birthplace to final layer positions. Dysregulated radial migration can engender cortical mis-lamination, leading to neurodevelopmental disorders. Epigenetic factors, including chromatin remodelers have emerged as formidable regulators of corticogenesis. Notably, the chromatin remodeler BAF complex has been shown to regulate several aspects of cortical histogenesis. Nonetheless, our understanding of how BAF complex regulates neuronal migration is limited. Here, we report that BAF complex is required for neuron migration during cortical development. Ablation of BAF complex in the developing mouse cortex caused alteration in the cortical gene expression program, leading to loss of radial migration-related factors critical for proper cortical layer formation. Of note, BAF complex inactivation in cortex caused defective neuronal polarization resulting in diminished multipolar-to-bipolar transition and eventual disruption of radial migration of cortical neurons. The abnormal radial migration and cortical mis-lamination can be partly rescued by downregulating WNT signaling hyperactivity in the BAF complex mutant cortex. By implication, the BAF complex modulates WNT signaling to establish the gene expression program required for glial fiber-dependent neuronal migration, and cortical lamination. Overall, BAF complex has been identified to be crucial for cortical morphogenesis through instructing multiple aspects of radial neuronal migration in a WNT signaling-dependent manner. [ABSTRACT FROM AUTHOR]

The localization and distribution of microgliocytes in the spinal cord (SC) of rat embryos during the formation of motor neuron precursors were studied. Antibodies to the Iba1 protein were used for the identification of microglial cells. To study the dynamics of the development of embryonic SC cells, we used the following immunohistochemical markers: vimentin (a marker of radial glia cells), doublecortin (a marker of neuroblasts), and synaptophysin (a marker of synaptic vesicles). It is shown that microglia progenitors penetrate the dorsal part of the spinal cord on day 12 of embryonic development; they are detected in the area of emerging motor neurons on day 14. It was found that embryonic microgliocytes are in close relationship with the processes of the radial glia and the processes of the neuroblasts of the anterior horns. The study into the dynamics of the development of the rat embryonic SC and the comparison of the processes of its histogenesis with the localization and morphological changes of the embryonic microglia indicates its participation in synaptogenesis and the differentiation of motor neurons (neuronogenesis). [ABSTRACT FROM AUTHOR]

Glioblastoma (GBM) is the most common primary brain malignancy, but much remains unknown about the histogenesis of these tumors. In the great majority of cases, GBM is a purely glial tumor but in rare cases the classic-appearing high-grade glioma component is admixed with regions of small round blue cells with neuronal immunophenotype, and these tumors have been defined in the WHO 2016 Classification as "glioblastoma with a primitive neuronal component." In this paper, we present two cases of GBM-PNC with highly divergent clinical courses, and review current theories for the GBM cell-of-origin. GBM-PNC likely arises from a cell type competent to give rise to glial or neuronal lineages. The thesis that GBM recapitulates to some extent normal neurodevelopmental cellular pathways is supported by molecular and clinical features of our two cases of GBM-PNC, but more work is needed to determine which cellular precursor gives rise to specific cases of GBM. GBM-PNC may have a dramatically altered clinical course compared to standard GBM and may benefit from specific lines of treatment. [ABSTRACT FROM AUTHOR]

In mycosis fungoides (MF), cutaneous granuloma formation is unusual. Furthermore, MF showing interstitial granuloma, a rare type, after combination therapy with interferon‐gamma (IFN‐γ) and narrowband UVB (nbUVB) has not been previously reported. A 77‐year‐old man was referred to our hospital with a 2‐month history of erythroderma. Biopsied specimens revealed infiltration of atypical lymphocytes and eosinophils. A diagnosis of an erythrodermic variant of MF was made. He was treated with combination therapy of IFN‐γ and nbUVB. After the therapy, papules newly appeared and a histopathological specimen revealed interstitial granuloma. There were several CXCR3‐positive cells around the granuloma. We speculated that the combination therapy made T‐helper 1 cells migrate to the cutaneous lesion and resulted in the granuloma formation. Furthermore, judging from the disappearance of elastic fibers around the interstitial granuloma, we considered that IFN‐γ may induce the infiltration of histiocytes interstitially after damage of elastic fibers caused by nbUVB therapy, and both IFN‐γ and nbUVB may thus play an important role in the histogenesis. Not only histopathology but also immunological observations are needed to elucidate the mechanisms underlying the development of different types of granuloma in MF. [ABSTRACT FROM AUTHOR]