Pigment Deposition Research Articles

Plumage and eggshell colouration covary with the level of sex-specific parental contributions to nest building in birds

Interspecific variation in sex-specific contributions to prenatal parental care, including avian nest building, is becoming increasingly better understood as we amass more information on more species. We examined whether sex-specific nest building contributions covary with the colouration of parents and their eggs in 521 species of Western Palearctic birds. Having colourful plumage and laying colourful eggs are costly because of the deposition of pigments in feathers and eggs and/or forming costly nanostructural substrates in feathers, and so it might be expected that those costs covary with the costs of nest building at the level of individuals and/or across species to produce of a suite of codivergent traits. Using a phylogenetically informed approach, we tested the hypothesis that species in which females alone invest energy building nests exhibit less sexual plumage dichromatism. However, we found comparative support for the opposite of this prediction. We then tested that species in which females alone build nests lay more colourful, and costlier, eggs because the dual costs of building nests and laying colourful eggs can only be borne by higher quality individuals. As expected, we found that species in which females build nests alone or together with males are more likely to lay colourfully pigmented eggs relative to species in which only males build nests. Finally, stochastic character mapping provided evidence of the repeated evolution of female-only nest building. Interspecific sex differences in plumage colouration therefore covary in a complex manner with female pre- (nest building) and post-copulatory (egg production) investment in reproduction.

A literary review article on Agnikarma in Kamala

Jaundice is defined as a yellowish discoloration of skin, mucous membrane and sclera due to the deposition of bile pigment (bilirubin). It can be classified as pre-hepatic, hepatic and post hepatic jaundice. The causes of various forms of Jaundice are either acquired or congenital. The incidence of jaundice in India is 2.37-3.15 per 1000 population. Varied reasons result in jaundice. Some of them are medically managed whereas some require surgical interventions. The underlying causative factors and clinical manifestations in such conditions are similar to Kamala described in Ayurveda. Various treatment protocols have been mentioned by various Acharya in their respective Samhita. One among them is a handbook for an Ayurvedic physician from Andhra Pradesh, written by Basavaraju named as Basavarajiyam where he has mentioned Agnikarma in Kamala Vyadhi which is a unique practice that might help for early recovery of patients. Another famous book on Viddha and Agnikarma Chikitsa by Dr.R.B. Gogate from Maharashtra also mentions about similar kind of treatment. By considering all these, the present article is aimed at understanding the textual references of Agnikarma in Kamala.

The sucker-like end-to-side arterial anastomosis for free flap in extremities reconstruction: a retrospective study of 78 cases

BackgroundThe application of end-to-side (ETS) anastomosis for flap transfer poses challenges, particularly in cases of significant size discrepancy between the donor and flap arteries. Herein, a novel ETS anastomosis technique, termed “sucker-like ETS anastomosis”, is developed to mitigate and rectify such vessel discrepancies. This study aims to evaluate the efficacy of this technique in tissue defect reconstruction through free flap transfer.MethodsBetween September 2018 and March 2023, the medical records and follow-up data of 78 patients who underwent free flap transfer using sucker-like ETS anastomosis for significant artery size discrepancies were collected and retrospectively analyzed.ResultsAmong the 78 cases that received free flap transfer, the range of artery size discrepancy (flap artery vs donor artery) was 1:1.6–1:4 (mean: 1:2.5). Following anastomosis with the sucker-like ETS technique, 75 cases achieved flap survival without requiring additional surgical intervention, yielding a one-stage success rate of 96.2%. Three cases experienced post-operative venous crises, with two cases surviving after vein exploration and one case undergoing flap necrosis, necessitating a secondary skin graft. Seven cases faced delayed wound healing but eventually achieved complete healing following dressing changes. No arterial crisis was observed during hospitalization. With an average follow-up of 13 months, the surviving flaps exhibited excellent vitality without flap necrosis or pigment deposition. Overall, the application of sucker-like ETS arterial anastomosis for flap transfer resulted in a high overall surgical success rate of 98.7% (77/78).ConclusionThe application of sucker-like ETS anastomosis for free flap transfer is highly effective, particularly in cases with significant size discrepancy between the recipient and donor arteries.

Comparative study on the effects of different polishing methods on tooth surface microstructure and roughness following initial periodontal treatment.

To investigate the effects of different polishing methods on the surface microstructure and roughness of teeth following initial periodontal treatment. Teeth were divided into three groups (silica onegloss, polishing disc, and polishing strip) in vitro. Tooth surface microstructure was characterized via scanning electron microscopy. Roughness was measured by profilometry and laser scanning confocal microscopy (LSCM). According to the in vitro results, one group was chosen for further clinical trials. Effects of the chosen polishing method on patient plaque control and satisfaction were assessed via plaque staining and visual analog scale (VAS). Electron microscopy results revealed that the polishing disc group had smoother roots and crowns than did the other two groups. Roughness analysis revealed that the crown roughness with the polishing disc and silica onegloss was lower, and the root roughness with the polishing disc was the lowest (p < .05) The LSCM results showed that the pigment deposition depth with the polishing disc and silicon onegloss in the crowns and roots were significantly lower than those with the other two methods (p = .000). The polishing effect of the polishing disc was best among the three groups. Clinical trials were performed to verify the polishing disc effects. Plaque staining results showed that the decrease in plaque in the polishing disc group was greater than that ofthe rubber cup group (p = .020), which was similar to the results of LSCM. The VAS results showed that the polishing disc made teeth feel smoother, similar to the results of the roughness detection, and the procedure was more comfortable (p < .05). However, there was no significant difference between the two groups regarding foreign body sensation during pronunciation (p = .178). Combining in vitro and in vivo evaluations, the use of a polishing disc following periodontal treatment yielded superior polishing effects on teeth and was better accepted by patients.

Pigment deposits in the retrolental space of Berger: a rare feature of pigment dispersion syndrome?

Pigment deposits in the retrolental space of Berger: a rare feature of pigment dispersion syndrome?

Rodents show darker and redder coloration in warm and rainy environments

AbstractAimAnimal coloration varies in response to environmental conditions. One well‐known principle, Gloger's rule, suggests that warmer and wetter environments lead to more pigmented animals. Yet, the original formulation lacks differentiation between the two primary melanin pigments: eumelanin and pheomelanin. We examined spatial eumelanin and pheomelanin variation to unravel the impact of various ecological factors on pigment deposition, and to assess support for the complex version of Gloger's rule.LocationSouth America.Time PeriodContemporary.Major Taxa StudiedSigmodontine rodents.MethodsWe extracted pelage color data from 231 species and quantified the geographic variation in eu‐ and pheomelanin deposition. We performed linear multiple regression to investigate the influence of temperature, precipitation, predator diversity, and UVA‐B radiance in eumelanin (lightness) and pheomelanin (redness).ResultsOur findings support the original formulations of Gloger's rule. Rodents in warmer and rainier regions, which also entails greater exposure to UV radiation and a diverse range of predators, exhibit darker‐colored pelage. In addition, redder rodents prevail in warmer environments. However, contrary to the rule predictions, we observe a reversal for reddish patterns in relation to precipitation, with rainier regions showcasing more intense red rodents.Main ConclusionsOur study breaks new ground by investigating previously unexplored facets of Gloger's rule in a continental mammalian group. We discovered compelling evidence that darker and redder coloration aligns closely with temperature and rainfall gradients. Although we found support for eumelanin–pelage predictions, expectations for pheomelanin pigmentation were only partially met. Our results might suggest that selective pressures act differently on dark and reddish coloration, revealing that coloration patterns in response to climate are more intricate than previously formulated.

Goniotomy for pigmentary glaucoma: Case series report

Pigmentary glaucoma (PG) is characterized by pigment deposition in the trabecular meshwork, which may obstruct the aqueous outflow and result in elevation of intraocular pressure (IOP) with optic nerve damage associated with visual field defect. There were three eyes (two patients) of PG who underwent 120° and 240° goniotomy (GT). At the 12-month follow-up visit, IOP of all cases was controlled with a reduction of ocular hypotensive medications. In conclusion, GT is effective and safe for PG, with the advantage of preserving the conjunctiva, and may be an appropriate surgical treatment for PG.

Whole-genome resequencing reveals genetic diversity, differentiation, and selection signatures of yak breeds/populations in southwestern China.

The Sichuan-Yunnan region is the main production area of yaks in southwestern China, with rich genetic resources of Yaks. Nevertheless, there have been limited study on the genetic characteristics of the entire yak populations in Tibet and southwestern China. In this study, we performed whole-genome resequencing to identify genetic variation information in a total of 198 individuals from six yak breeds (populations) in Sichuan (Muli yak, Jinchuan yak, Changtai yak, Maiwa yak), Yunnan (Zhongdian yak), and Tibet (Tibetan yak). The aim was to investigate the whole-genome genetic diversity, population genetic structure, and genome selection signatures. We observed that all six populations exhibit abundant genetic diversity. Except for Tibetan yaks, which showed low nucleotide diversity (0.00104), the remaining yak populations generally displayed high nucleotide diversity (0.00129-0.00153). Population genetic structure analysis revealed that, among the six yak populations, Muli yak exhibited greater differentiation from other yak populations and formed a distinct cluster independently. The Maiwa yak population displayed a complex genetic structure and exhibited gene exchange with Jinchuan and Changtai yaks. Positive selection signals were detected in candidate genes associated with growth (GNB4, HMGA2, TRPS1, and LTBP1), reproduction (PI4KB, DYNC1I1, and GRIP1), immunity (CD200 and IL1RAP), lactation (SNX13 and CPM), hypoxia adaptation (NDUFB6, PRKN, and MRPS9), hair (KRT24, KRT25, and KRT26), meat quality (SUCLG2), digestion and absorption (CLDN1), and pigment deposition (OCA2) using the integrated Pi and F ST methods. This study provides significant insights into understanding the whole-genome genetic characteristics of yak populations in Tibet and southwestern China.

Manchas de Wischnewsky em casos de hipotermia fatal em bovinos

ABSTRACT: Wischnewsky spots (WS) are hemorrhagic, non-erosive, and non-ulcerative lesions that affect the gastric mucosa. They are considered common in the stomachs of humans who have died from hypothermia and are rarely described in other animal species. This study describes the occurrence of WS in cattle that had died of hypothermia in two cities in the state of Mato Grosso do Sul. Two properties were visited, and three cattle were necropsied by the team from the Pathological Anatomy Laboratory of the Federal University of Mato Grosso do Sul (LAP-UFMS). The epidemiological conditions and clinical signs of the cattle examined on both properties were similar. The deaths occurred on days when there was a sudden drop in environmental temperature, with continuous rain for more than 24 hours. During the visits, the most affected live cattle were found in sternal decubitus, with their heads resting on their flanks, or laterally in a comatose state, with nystagmus and a rectal temperature below 32°C. Macroscopically, there were multifocal to coalescent red and black areas on the mucosal surface of the abomasums of the three cattle necropsied, mainly at the apex of the folds, oval or punctate in shape, measuring 0.1 to 1.0cm in diameter. Microscopically, these dark areas corresponded to areas of rarefaction of the mucosal epithelial cells associated with hemorrhage and the frequent deposition of golden-brown pigment (hematin) in the extracellular medium. The diagnosis of hypothermia in cattle was based on epidemiology, clinical-pathological examination, and the exclusion of differential diagnoses. The lesions found in the abomasum of cattle that had died from hypothermia were compatible with WS, highlighting the importance of recognizing them in cases of cattle deaths in which this condition is suspected.

Subconjunctival deferoxamine for corneal rust deposits associated with ocular siderosis: A case report

Introduction: Ocular siderosis is a vision-threatening condition resulting from intraocular iron toxicity. This case re-establishes a role for subconjunctival deferoxamine, a chelating agent uncommonly used in ophthalmology, as an adjunctive treatment for ocular siderosis. Case Report: A 37-year-old healthy male presented two months after an injury at work with intermittent pain and blurry vision in the right eye. Presenting visual acuity (VA) was 20/100 in the right eye. With delayed presentation, the patient already had ocular siderosis with corneal rust deposits and retinal damage. The patient underwent pars plana vitrectomy (PPV) with surgical view impaired by corneal deposits and intraocular metallic intraocular foreign body (IOFB) that disintegrated upon attempted removal. At six months postoperatively, VA was 20/70 in the right eye, and examination revealed worsened diffuse, pigmented subepithelial deposits in the central cornea, iris atrophy, cotton wool spots, optic nerve pallor, and a residual IOFB in the anterior vitreous, consistent with worsened ocular siderosis. Superficial keratectomy was performed in combination with repeat PPV to improve surgical visualization and aid in IOFB removal. An amniotic membrane was placed and a subconjunctival injection of deferoxamine was administered. The cornea was well-healed with significantly improved siderosis and no epithelial defects on 2-week postoperative follow-up. Visual acuity was 20/60 at last follow-up two months postoperatively after second surgery. Conclusion: In treating ocular siderosis, subconjunctival injection of deferoxamine can be a useful addition to surgical IOFB removal to prevent the accumulation of iron deposits in the anterior segment of the eye.

Synergetic construction of color and multifunction for sustainable lyocell fabric by microbial nano pigment

As a kind of low-carbon, environmentally friendly and high-quality regenerated cellulose fiber derived from nature plant, the promotion and application of lyocell fiber is attracting much attention. In this paper, for the first time, microbial pigment was applied for color and multifunction construction of lyocell fabric. The size change of the pigment nano-particles during the color construction process was explored to verify the dyeing mechanism of nano-suspension system, and the optimal dyeing condition was obtained. In order to improve the dyeing effect and functionality of fabric, 1,2,3,4-butanetetracarboxylic acid (BTCA) was used to realize the anionic modification of lyocell fabric with high strength retention rate. Under optimal color construction condition, the color depth of the modified fabric was 298.5% higher than that of the unmodified one, and the dyed fabric possessed excellent dyeing uniformity and permeability. Moreover, the crosslinking reaction between BTCA and cellulose macromolecules, as well as the pigment deposition inside the fibers were helpful to the fibrillation prevention function of lyocell fibers. Dyed fabrics inherited the antibacterial and ultraviolet absorption properties of prodigiosins. The bacteriostatic rate against Staphylococcus aureus was above than 98.5%, and the UV protection performance was obviously improved. This technology successfully realized the color and multi-functional construction of the lyocell fabric in one step by natural pigment from microorganism.

Microalgae as functional feed for Atlantic salmon: effects on growth, health, immunity, muscle fatty acid and pigment deposition

Microalgae are increasingly being investigated as functional feed additives in a variety of fish species, but our knowledge on how microalgae supplementation affects Atlantic salmon remains limited. We hypothesized that microalgae inclusion of 8% in the feed would improve performance, fatty acid and pigment deposition as well as health and immunity of Atlantic salmon reared in recirculating aquaculture systems (RAS). We fed Atlantic salmon smolts with five different microalgae enriched diets containing Tetraselmis chuii (TC), Arthrospira platensis (AP), Schizochytrium limacinum (SL) or Chlorella vulgaris, either intact (CVI) or as broken cell wall derivative (CVB) or a control diet (CD). After eight weeks of feeding in brackish water (13 psu), all groups were transferred to seawater (32 psu) for additional two weeks. Our results indicate that CVB improved feed conversion and protein retention, but reduced condition factor (p &amp;lt; 0.05) compared to fish fed with a control diet. Voluntary feed intake decreased in seawater, but was similar among diet groups. The amount of docosahexaenoic acid was particularly high in SL-fed fish and alpha-linolenic acid was enriched in fish fed CVI, CVB and TC (p &amp;lt; 0.05). Following seawater transfer, fat content and monounsaturated fatty acids decreased in the muscle, while polyunsaturated fatty acids increased. Lutein was present in all muscle samples, but highest concentrations were found in CVB-, CVI- and TC-fed fish. In the anterior intestine, microalgae supplementation induced differentially regulated trout protein 1 (drtp1) expression in CVI- and CVB-fed fish, but reduced the expression of interleukin 1 and 10 receptor (il1r2 &amp;amp; il10rb) in CVI-fed fish. In the liver, feeding CVI and SL induced complement C1q like 2 (c1ql2) expression, while reducing serum amyloid A5 (saa5) expression. Superoxide-dismutase protein concentration was induced in the liver of fish fed SL, while myeloperoxidase was reduced in most microalgae-fed groups. In conclusion, we show that commercially relevant microalgae can be used as functional feed additives for Atlantic salmon promoting different health aspects without negatively affecting their growth performance when cultivated in RAS.

Comparative analysis of hepatic transcriptomes and metabolomes of Changshun green-shell laying hens based on different green eggshell color intensities

The eggshell color of avian species is an important trait that is predominantly determined by the pigments biliverdin and protoporphyrin. Various factors affect eggshell pigment deposition and coloration; however, the underlying mechanisms remain unclear. We analyzed the hepatic transcriptomes and metabolomes of Changshun green-shell hens laying dark green and light green eggs to investigate the potential role of the liver in regulating the intensity of the green eggshell color. In total, 350 differentially expressed genes and 211 differentially altered metabolites were identified. Gene set enrichment analysis revealed that the enriched pathways and Gene Ontology (GO) terms were mainly associated with energy, immunity, and nutrient metabolism. Metabolite set enrichment analysis revealed that the enriched pathways were mainly associated with amino acid, vitamin, bile acid, and lipid metabolism. Moreover, gene-metabolite interaction network analysis revealed 1 subnetwork. Most genes and metabolites in this subnetwork were determined to be related to melanin metabolism and transport. In conclusion, our results suggest that hepatic melanin metabolism and transport are critical for eggshell coloration. Six candidate genes (CDKN2B, DDC, PYCR1, ABCG5, SLC3A1, and P2RX2) and 7 candidate metabolites (serotonin, 5-hydroxyindoleacetic acid, ornithine, acetylcholine, L-tryptophan, D-ornithine, and ADP) were suggested to play important roles in this process. Meanwhile, this study suggests that changes in hepatic energy metabolism, immune status, antioxidation activity, nutrient availability, and bile acid synthesis can impair eggshell coloration.

Hemosiderin induced acute kidney injury requiring hemodialysis in patients with paroxysmal nocturnal hemoglobinuria: A case report.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematopoietic stem cell disease with features of hemolytic anemia, thrombosis, and bone marrow failure. Due to intravascular hemolysis and hemoglobinuria, renal dysfunction is often accompanied in PNH patients. A 25-year old woman presenting gross hematuria after coronavirus disease 2019 infection was admitted to our medical center. She had mild nausea and headache. She was diagnosed with iron deficiency anemia few years ago and had no other underlying disease. Her laboratory findings showed acute kidney injury (AKI) and severe anemia, with evidences of hemolysis. Renal biopsy was done to determine the cause of renal failure and the result was acute tubular necrosis with deposition of golden pigments, hemosiderin. With pathologic result and laboratory finding of hemolysis, we did flow cytometry for PNH, and the patient was finally diagnosed with PNH. With AKI and oliguria, the patient started to take hemodialysis. After taking 5 sessions of hemodialysis, the patient's renal function was recovered from AKI. With diagnosis of PNH, the patient is now being treated with complement C5 inhibitor. This challenging case tells us that we should consider the first manifestation of PNH as a cause of severe AKI requiring hemodialysis in a patient with anemia and evidence of hemolysis.

Conditional loss of Ube3d in the retinal pigment epithelium accelerates age-associated alterations in the retina of mice.

Several studies have suggested a correlation between the ubiquitin-proteasome system (UPS) and age-related macular degeneration (AMD), with its phenotypic severity ranging from mild visual impairment to blindness, but the mechanism for UPS dysfunction contributing to disease progression is unclear. In this study, we investigated the role of ubiquitin protein ligase E3D (UBE3D) in aging and degeneration in mouse retina. Conditional knockout of Ube3d in the retinal pigment epithelium (RPE) of mice led to progressive and irregular fundus lesions, attenuation of the retinal vascular system, and age-associated deterioration of rod and cone responses. Simultaneously, RPE-specific Ube3d knockout mice also presented morphological changes similar to the histopathological characteristics of human AMD, in which a defective UPS led to RPE abnormalities such as phagocytosis or degradation of metabolites, the interaction with photoreceptor outer segment, and the transport of nutrients or waste products with choroidal capillaries via Bruch's membrane. Moreover, conditional loss of Ube3d resulted in aberrant molecular characterizations associated with the autophagy-lysosomal pathway, oxidative stress damage, and cell-cycle regulation, which are implicated in AMD pathology. Thus, our findings strengthen and expand the impact of UPS dysfunction on retinal pathophysiology during aging, indicating that genetic Ube3d deficiency in the RPE could lead to the abnormal formation of pigment deposits and secondary fundus alterations. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Disrupting the Repeat Domain of Premelanosome Protein (PMEL) Produces Dysamyloidosis and Dystrophic Ocular Pigment Reflective of Pigmentary Glaucoma.

Pigmentary glaucoma has recently been associated with missense mutations in PMEL that are dominantly inherited and enriched in the protein's fascinating repeat domain. PMEL pathobiology is intriguing because PMEL forms functional amyloid in healthy eyes, and this PMEL amyloid acts to scaffold melanin deposition. This is an informative contradistinction to prominent neurodegenerative diseases where amyloid formation is neurotoxic and mutations cause a toxic gain of function called "amyloidosis". Preclinical animal models have failed to model this PMEL "dysamyloidosis" pathomechanism and instead cause recessively inherited ocular pigment defects via PMEL loss of function; they have not addressed the consequences of disrupting PMEL's repetitive region. Here, we use CRISPR to engineer a small in-frame mutation in the zebrafish homolog of PMEL that is predicted to subtly disrupt the protein's repetitive region. Homozygous mutant larvae displayed pigmentation phenotypes and altered eye morphogenesis similar to presumptive null larvae. Heterozygous mutants had disrupted eye morphogenesis and disrupted pigment deposition in their retinal melanosomes. The deficits in the pigment deposition of these young adult fish were not accompanied by any detectable glaucomatous changes in intraocular pressure or retinal morphology. Overall, the data provide important in vivo validation that subtle PMEL mutations can cause a dominantly inherited pigment pathology that aligns with the inheritance of pigmentary glaucoma patient pedigrees. These in vivo observations help to resolve controversy regarding the necessity of PMEL's repeat domain in pigmentation. The data foster an ongoing interest in an antithetical dysamyloidosis mechanism that, akin to the amyloidosis of devastating dementias, manifests as a slow progressive neurodegenerative disease.

Analysis of a patient with early-onset retinitis pigmentosa due to novel variants of CRB1 gene

To explore the genetic basis for a patient with early-onset retinitis pigmentosa (RP). A patient who had presented at the West China Hospital of Sichuan University on March 10, 2020 was selected as the study subject. The patient and his parents were subjected to whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing and in silico analysis. The patient has featured substantial loss of binocular vision field. Funduscopy revealed characteristic bone spicule-type pigment deposits, as well as attenuated retinal arterioles and pale-appearing optic discs. WES revealed that he has harbored compound missense variants of a RP-associated CRB1 gene, including c.2969T>C (p.Leu990Ser) and c.1816T>C (p.Cys606Arg), which were respectively inherited from his father and mother. Homozygous c.1816T>C (p.Cys606Arg) variant has been identified among RP patients, whilst the c.2969T>C (p.Leu990Ser) variant was unreported previously. Both variants were predicted as likely pathogenic based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). The novel compound heterozygous variants of the CRB1 gene probably underlay the early-onset RP in this patient. Above finding has enriched the mutational spectrum of the CRB1 gene.

Research Progress on Anthocyanin-Mediated Regulation of 'Black' Phenotypes of Plant Organs.

The color pattern is one of the most important characteristics of plants. Black stands out among the vibrant colors due to its rare and distinctive nature. While some plant organs appear black, they are, in fact, dark purple. Anthocyanins are the key compounds responsible for the diverse hues in plant organs. Cyanidin plays an important role in the deposition of black pigments in various plant organs, such as flower, leaf, and fruit. A number of structural genes and transcription factors are involved in the metabolism of anthocyanins in black organs. It has been shown that the high expression of R2R3-MYB transcription factors, such as PeMYB7, PeMYB11, and CsMYB90, regulates black pigmentation in plants. This review provides a comprehensive overview of the anthocyanin pathways that are involved in the regulation of black pigments in plant organs, including flower, leaf, and fruit. It is a great starting point for further investigation into the molecular regulation mechanism of plant color and the development of novel cultivars with black plant organs.

Oral Soft Tissue Lesions in Children

Lips, teeth, gums, oral mucous membranes, palate, tongue, and the oral lymphoid system comprise the oral cavity. Oral cavity soft tissue lesions are extremely common in children, and they can present clinically as coloured lesions, mucosal ulceration, or Nodular lesions. The appearance of the oral mucosa alters to reflect the underlying health status, which could be local or systemic. While most oral diseases can be diagnosed visually, some disorders can be befuddling, and their diagnoses can be elusive. Pigmentation is defined as the process of pigment deposition in tissues. This article provides a brief overview of oral pigmented lesions in children Keywords: oral soft tissue lesions, mucosal abnormalities, children, paediatric dentistry

CLINICAL CASE OF RECURRENT NEVUS

Abstract. Introduction. Recurrent nevus is a benign proliferation of melanocytes that occurs at the site of non-radical removal of a previously existing nevus. Recurrence rates range from 0.3% to 28% and most often occur within 6 weeks to 6 months after removal. Clinically recurrent nevus is characterized by uneven pigmentation with uneven edges in the area of the scar.&#x0D; Walton et al. began researching the phenomenon of recurrent nevus in 1957. In 1975, Kornberg and Ackerman reported that a pigmented recurrent nevus can resemble superficially spreading melanoma both clinically and histologically, and proposed the term pseudomelanoma to describe this benign phenomenon. Currently, the term is rarely used, but it motivates a thorough examination of patients with such a problem.&#x0D; Case presentation. Patient A. complained about the presence of a formation in the area of the outer surface of the right forearm, which has existed for many years, it was injured several times, but has recently changed the colour. On examination, a nodule up to 0.5 cm in size, heterogeneously pigmented, with peripheral erythema was found in the indicated place. During dermoscopy, chaotic unevenly distributed pigmentation, consisting of dots, globules, forming a cellular structure in a scattered manner is determined, zones of segmental radial lines are present as well. The vascular pattern in the central part of the formation is not defined, on the periphery it is represented by slightly noticeable point vessels. Digital post-processing using machine learning technology was carried out to improve visualization of blood supply. Multiple point, curved, and convoluted vessels with few branches around the formation, and several central vessels in the pigment cells are determined. Surgical removal of the tumor was performed with involvement of the erythema zone, taking into account the peculiarities of pigmentation and vascular pattern. The pathogistological structure is presented in the photomicrograph. The epidermis has a typical structure, with areas of slight acanthosis; hyperpigmentation of the basal layer is also observed. In the dermis, foci of brown pigment deposition, single lymphocytes, there are areas of intradermal lobular-horizontal fibrosis with angiomatosis and scattered lymphocytic infiltration. Taking into account the clinical data, there is a recurrence of a melanocytic nevus on the background of a skin scar (Recurrent neavus).&#x0D; Teaching point. Dermoscopy allows obtaining additional data for the differential diagnosis of recurrent nevus and recurrent melanoma. A recurrent nevus is characterized by relative symmetry of formation and a pattern of segmental radial lines. The formation is limited to the area of the scar and does not go beyond it. Also, in the case of recurrent melanoma, a continuous growth in dynamics and a later appearance of recurrence from the moment of intervention will be obvious.&#x0D; Conclusions. As clinical practice demonstrates, under certain circumstances, recurrent pigmentation can be observed in cases of nevi that have been traumatized. It will be visible both dermoscopically and pathohistologically. Sometimes it is difficult even for experts to distinguish between a highly irritated nevus and a melanoma.