Fibrous Tissue Research Articles

Anatomopathological characterization of branchial cysts in slaughtered pigs

Branchial cysts are a congenital anomaly in humans and other animal species. In this study, twenty commercially bred slaughtered pigs ranging from 120 to 150 days of age, sourced from different farms and lots, were found to have cysts in the oropharyngeal region at meat inspection despite the absence of clinical signs. Two cysts were selected for histopathological examination. The first cyst was surrounded by fibrous connective tissue and lined by a simple single cell layer of epithelium. The second cyst comprised a squamous pseudostratified to simple stratified epithelium, accompanied by a mild inflammatory infiltrate. This cyst was also surrounded by fibrous connective tissue and glands. The pathological diagnosis of branchial cysts in slaughtered pigs was established on the basis of their anatomical location and gross and microscopic findings.

Vocal fold restoration after scarring: biocompatibility and efficacy of an MSC-based bioequivalent

BackgroundThere is growing interest to application of regenerative medicine approaches in otorhinolaryngological practice, especially in the framework of the therapy of vocal fold (VF) scar lesions. The used conservative and surgical methods, despite the achieved positive outcomes, are frequently unpredictable and do not result in the restoration of the VF’s lamina propria’s structure, which provides the mechanical properties necessary for vibration. In this connection, the aim of this study was to ascertain the safety and efficacy of a bioequivalent in the treatment of VF scars using a rabbit model of chronic damage.MethodsThe bioequivalent consisted of a hydrogel system based on a PEG-fibrin conjugate and human bone marrow-derived MSC. It was characterized and implanted heterotopically into rats and orthotopically into rabbits after VF scar excision.ResultsWe showed that the fabricated bioequivalent consisted of viable cells retaining their metabolic and proliferative activity. While being implanted heterotopically, it had induced the low inflammatory reaction in 7 days and was well tolerated. The orthotopic implantation showed that the gel application was characterized by a lower hemorrhage intensity (p = 0.03945). The intensity of stridor and respiratory rate between the groups in total and between separate groups had no statistically significant difference (p = 0.96 and p = 1; p = 0.9593 and p = 0.97…1, respectively). In 3 days post-implantation, MSC were detected only in the tissues closely surrounding the VF defect. The bioequivalent injection caused that the scar collagen fibers were packed looser and more frequently mutually parallel that is inherent in the native tissue (p = 0.018). In all experimental groups, the fibrous tissue’s ingrowth in the adjacent exterior muscle tissue was observed; however, in Group 4 (PEG-Fibrin + MSC), it was much less pronounced than it was in Group 1 (normal saline) (p = 0.008). The difference between the thicknesses of the lamina propria in the control group and in Group 4 was not revealed to be statistically significant (p = 0.995). The Young’s modulus of the VF after the bioequivalent implantation (1.15 ± 0.25 kPa) did not statistically significantly differ from the intact VF modulus (1.17 ± 0.45 kPa); therefore, the tissue properties in this group more closely resembled the intact VF.ConclusionsThe developed bioequivalent showed to be biocompatible and highly efficient in the restoration of VF’s tissue.

Need for transverse strain data for fitting constitutive models of arterial tissue to uniaxial tests

The study deals with the process of estimation of material parameters from uniaxial test data of arterial tissue and focuses on the role of transverse strains. Two fitting strategies are analyzed and their impact on the predictive and descriptive capabilities of the resulting model is evaluated. The standard fitting procedure (strategy A) based on longitudinal stress-strain curves is compared with the enhanced approach (strategy B) taking also the transverse strain test data into account. The study is performed on a large set of material data adopted from literature and for a variety of constitutive models developed for fibrous soft tissues. The standard procedure (A) ignoring the transverse strain test data is found rather hazardous, leading often to unrealistic predictions of the model exhibiting auxetic behaviour. In contrast, the alternative fitting method (B) ensures a realistic strain response of the model and is proved to be superior since it does not require any significant demands of computational effort or additional testing. The results presented in this paper show that even the artificial transverse strain data (i.e., not measured during testing but generated ex post based on assumed Poisson's ratio) are much less hazardous than total disregard of the transverse strain response.

Surgical outcomes in aggressive retinopathy of prematurity (AROP)-related retinal detachments.

Aggressive retinopathy of prematurity (AROP) is a severe and progressive variant of retinopathy of prematurity (ROP) rapidly forming fibrous tissue extending from the disc toward the posterior lens surface progressing to Stage 5 disease without traversing the classical course that includes Stages 1 to 3. Since AROP behaves differently from type 1 ROP, this study was undertaken to evaluate the surgical outcome of AROP-related detachments. Retrospective analysis of data from electronic medical records of babies diagnosed with AROP-related detachments who underwent micro-incision vitrectomy surgery (MIVS) was included. The demographic data, details of primary intervention (laser and/or intravitreal bevacizumab), and surgery were noted. In a subset of patients, surgical intervention was planned early at the onset of fibrovascular tissue. 43 eyes of 26 babies with median birth weight 1175 g and median gestational age of 29 weeks were analyzed. 42/43 eyes underwent primary intervention in form of laser and/or anti-VEGF injection before surgery. 41.8%, 25.5%, and 32.5% eyes progressed to stages 4A, 4B, and 5, respectively, requiring surgical intervention. 66% eyes underwent lensectomy and vitrectomy (LV), and 44% eyes underwent lens sparring vitrectomy (LSV). 58% eyes had attached macula. 44% eyes that had a relatively less vascular diseases had better anatomical outcome (P = 0.019). At final follow-up, 53.4% eyes followed or at least had light fixation, and 77.7% eyes undergoing LSV fixated and/or followed light compared to 33% for LV (P = 0.04). Challenges in AROP include rapid progression to advanced stages of ROP requiring close monitoring and multiple interventions. Surgeries for AROP have a favorable anatomical and functional outcome in 58% and 53%, respectively. Eyes undergoing lens sparing vitrectomy had better visual outcomes.

MORPHOLOGICAL CHARACTERISTICS AND CAUSES OF ATROPHIC SCAR TREAT WITH SUBCISION AND PLATELET-RICH PLASMA AT THE CAN THO DERMATO-VENEREOLOGY HOSPITAL IN 2021-2023

Background: Atrophic scars are the result of natural healing leading to the formation of replacement fibrous tissue. The atrophic scar is a common undesirable complication of acne, chickenpox, herpes, trauma, etc. Although the disease does not cause dangerous complications, due to the location of the lesions on the face, it causes great aesthetic and psychological obstacles, and the patient is less confident in communication, profoundly affecting the patient's quality of life. and labor productivity. The combination of subcision and platelet-rich plasma (PRP) in the treatment of atrophic scars is a new method applied in recent years. The morphological characteristics and causes of them may affect the results of subcision and platelet-rich plasma treatment. Objectives: To describe the clinical characteristics and causes of atrophic scars in patients at Can Tho Dermato-Venereology Hospital from 4/2021 to 6/2023. Materials and methods: A cross-sectional descriptive study was carried out on 30 patients with atrophic scars who were treated with subcision and platelet-rich plasma at Can Tho Dermato-Venereology Hospital in 2021 –2023. Results: the average age of onset of atrophic scars was 21.27 ± 4.085 years old, and the average duration of atrophic scars was 6.33 ± 4.31 years. The majority of patients had acne scars, accounting for 90%; only 6.7% had post-varicella scars; and 3.3% had traumatic scars. 70% with mixed scars, and the common rate of boxscar (83.3%). Scars on the cheek were 100%, and 80% of patients appear to have atrophic scars in multiple locations. Scars color as normal skin accounted for 66.7%. The most atrophic scar patients classified as grade 3 accounted for 66.7%, grade 4 accounted for 23.3%, and at least level 2 accounted for 10%. Conclusions: Facial atrophic scars are mainly the result of acne. Most of them have mixed scars, boxscar are common. Atrophic scars are mainly distributed on the cheeks and in multiple locations. And grade 3 accounts for the majority.

Atelocollagen Scaffold Enhances Cartilage Regeneration in Osteochondral Defects: A Study in Rabbits.

To enhance articular cartilage healing, microfractures (Mfx) and bone marrow aspirate concentrate (BMAC) are commonly used, and some form of scaffold is often used together to increase its efficacy. Herein, we compared the efficacy of atelocollagen scaffold to that of collagen scaffold when used with Mfx or BMAC on osteochondral defect of animal. This experiment was designed in two stages, and therapeutic effects of Mfx and BMAC were respectively evaluated when used with atelocollagen or collagen scaffold. Femoral condyle defects were artificially created in male New Zealand White rabbits, and in each stage, 12 rabbits were randomly allocated into three treatment groups: test group with additional atelocollagen scaffold, the positive control group with collagen scaffold, and the negative control group. Then, for 12weeks, macroscopic and histological evaluations were performed. At 12weeks, defects in the test group were fully regenerated with normal cartilage-like tissue, and were well integrated with the surrounding cartilage at both stages experiment, whereas defects in the control groups were not fully filled with regenerated tissue, and the tissue appeared as fibrous tissue. Histologically, the regenerated tissue in the test group showed a statistically significant improvement compared to the positive and negative control groups, achieving a similar structure as normal articular cartilage. The results showed that implantation of the atelocollagen scaffold enhanced cartilage regeneration following osteochondral defects in rabbits. This suggests that the atelocollagen scaffold can be used with Mfx or BMAC for effective regeneration of osteochondral defects.

Sterile inflammation, cross-presentation, autophagy and adaptive immunity in immunoinflammatory rheumatic diseases

Proinflammatory extracellular and intracellular DAMPs are the dominant etiological factors of sterile inflammation in immuno-inflammatory rheumatic diseases. They are generated by systemic progressive disorganization of loose fibrous unformed connective tissue, programmed cell death and cell necrosis. Sterile inflammation is a multi-stage process which is induced by a sequence of reactions mediated by leukocytes and resident cells of the macrophage-monocyte series, aimed at cleansing the focus of inflammation from cellular and tissue detritus, followed by restoration of homeostasis of damaged tissue. An important role in this process belongs to the transendothelial migration of leukocytes to the focus of sterile inflammation and formation of cellular inflammatory infiltrate. The key feature of these events is the reactivity of PRR receptors followed by a cascade of PRR-DAMPs interactions with subsequent launch of molecular and cellular processes causing the local and/or systemic manifestations of sterile inflammation. Activation of innate immunity is the result of PRR-DAMPs interactions which launches the molecular and cellular reactions. Hence, it is possible to attribute the immunoinflammatory rheumatic diseases to the category of systemic sterile autoinflammatory processes. Generalization of the pathophysiological effects of pro-inflammatory DAMPs and, accordingly, the systemic and multi-organ nature of tissue and internal organ damage in immunoinflammatory rheumatic diseases is due to the wide occurrence of receptors for “danger signals”. The most important place in the development of DAMP-mediated sterile inflammation is occupied by the phenomenon of cross-presentation and autophagy. The cross-presentation causes exposition of extracellular DAMPs from internalized proteins with MHC class I molecules to autoreactive CD8+ cytotoxic T lymphocytes. Autophagy provides processsing of intracellular peptide DAMPs, their loading onto MHC class II molecules with subsequent induction of adaptive immune response in CD4+T cell populations. The innate lymphoid cells (ILC) make an important contribution to these processes. The model of functional coupling and complementarity between ILCs and Th-CD4+T cells has expanded our understanding of immune regulation by extending the activity of innate and adaptive immunity to the level of maintaining tissue homeostasis, morphogenesis, repair, regeneration and inflammation. Progression of systemic sterile inflammation may be a result of PRR-DAMP interactions of tissue ILCs followed by switching of ILC/Th-CD4+T cell partners. The data presented in this review define the promising molecular and cellular targets aiming for regulation and/or inhibition of sterile inflammation in immunoinflammatory rheumatic diseases.

Correlation Analysis of Macrophage Distribution and Pathological Features of Carotid Atherosclerotic Plaque

Macrophages play a crucial role in sustaining chronic inflammation in atherosclerosis (AS) and are a hallmark of atherosclerotic plaques. They undergo differentiation into distinct subpopulations under the influence of oxidized lipids and cytokines, exerting various functions in plaque formation and progression. To examine the variations in the quantity and distribution of different macrophage subpopulations surrounding distinct pathological features of carotid plaques in human AS. Based on these findings, we seek to explore the potential correlations between specific macrophage subpopulations and AS pathological characteristics. Initially, we analyzed single-cell RNA sequencing (scRNA-Seq) data obtained from the GEO DataSets (GSE159677). The results revealed a significant infiltration of macrophages in AS, categorizing them into distinct subpopulations with diverse transcriptional features and functions. Furthermore, in different regions of AS (i.e., calcified AS core vs. proximal adjacent areas), both the total number of macrophages and the subpopulation ratios exhibited variations. Subsequently, we examined the distribution differences of macrophage subpopulations within 61 surgically resected AS plaques using marker staining techniques such as CD68, iNOS, Arg-1, CD163, and HO-1. The findings demonstrated that macrophages predominantly localized in specific pathological lesions, including necrosis, fibrous tissue degeneration, and cholesterol crystallization. Moreover, distinct subpopulations exhibited differential distribution patterns within these lesions. This study provides confirmation of extensive macrophage infiltration within atherosclerotic plaques, highlighting the presence of subtypes that exhibit variability across different pathological lesions. These results suggest that various macrophage subpopulations may contribute differently to distinct pathological lesions in AS.

3D-Printed Auxetic Skin Scaffold for Decreasing Burn Wound Contractures at Joints.

For patients with severe burns that consist of contractures induced by fibrous scar tissue formation, a graft must adhere completely to the wound bed to enable wound healing and neovascularization. However, currently available grafts are insufficient for scar suppression owing to their nonuniform pressure distribution in the wound area. Therefore, considering the characteristics of human skin, which is omnidirectionally stretched via uniaxial stretching, we proposed an auxetic skin scaffold with a negative Poisson's ratio (NPR) for tight adherence to the skin scaffold on the wound bed site. Briefly, a skin scaffold with the NPR effect was fabricated by creating a fine pattern through 3D printing. Electrospun layers were also added to improve adhesion to the wound bed. Fabricated skin scaffolds displayed NPR characteristics (-0.5 to -0.1) based on pulling simulation and experiment. Finger bending motion tests verified the decreased marginal forces (<50%) and deformation (<60%) of the NPR scaffold. In addition, the filling of human dermal fibroblasts in most areas (>95%) of the scaffold comprising rarely dead cells and their spindle-shaped morphologies revealed the high cytocompatibility of the developed scaffold. Overall, the developed skin scaffold may help reduce wound strictures in the joints of patients with burns as it exerts less pressure on the wound margin.

Asherman's Syndrome: A Comprehensive Review of Pathophysiology, Diagnosis, and Treatment Strategies

Asherman's Syndrome, also known as intrauterine adhesions or synechiae, is a rare but clinically significant condition characterized by the formation of fibrous tissue within the uterine cavity, resulting in adhesions and obliteration of the endometrial cavity. This condition often leads to a spectrum of menstrual disturbances, infertility, and recurrent pregnancy loss. The purpose of this comprehensive review article is to elucidate the multifaceted aspects of Asherman's Syndrome, encompassing its pathophysiological mechanisms, diagnostic challenges, and various treatment modalities. A thorough understanding of this syndrome is crucial for healthcare providers to offer optimal care and management options to affected patients, ultimately improving their reproductive outcomes and quality of life.

Gelatin methacryloyl hydrogel with and without dental pulp stem cells for TMJ regeneration: An invivo study in rabbits.

In the last decade, tissue-engineering strategies for regenerating the temporomandibular joint (TMJ) have been investigated. This may be a promising strategy for the minimally invasive restoration of joint integrity. To evaluate whether dental pulp stem cells (DPSCs) loaded in a light-occured hydrogel made of gelatin methacryloyl (GelMA) enhance the regeneration of osteochondral defects in the rabbit TMJ. Defects were filled with GelMA alone (control group; n = 4) or filled with GelMA loaded with rabbit DPSCs (experimental group; n = 4), In one group, the TMJ capsule was opened without creating a defect (sham group; n = 2). The following micro-CT parameters were analysed: bone volume to total volume ratio (BV/TV%) and bone mineral density (BMD). Histological evaluation was performed to assess cartilage regeneration features. A semi-quantitative scoring system was also used to evaluate the defects. All groups had no statistical difference regarding the micro-CT parameters. The highest mean healing score was found for the experimental group. After 4 weeks, there were no signs of hydrogel in either group or no signs of inflammation in the adjacent tissues. The tissue formed in the defect was dense fibrous connective tissue. Adding DPSCs to GelMA did not provide a regenerative enhancement in TMJ osteochondral defects. This resulted in similar micro-CT parameters after 4 weeks of healing, with improved signs of subchondral bone regeneration but no cartilage regeneration.

Liver fibrosis emulation: Impact of the vascular fibrotic alterations on hemodynamics

The liver circulatory system comprises two blood supply vascular trees (the hepatic artery and portal venous networks), microcirculation through the hepatic capillaries (the sinusoids), and a blood drainage vascular tree (the hepatic vein network). Vasculature changes due to fibrosis —located predominantly at the microcirculation level— lead to a marked increase in resistance to flow causing an increase in portal pressure (portal hypertension). Here, we present a liver fibrosis/cirrhosis model. We build on our 1D model of the healthy hepatic circulation, which considers the elasticity of the vessels walls and the pulsatile character of blood flow and pressure, and recreate the deteriorated liver vasculature due to fibrosis. We emulate altered sinusoids by fibrous tissue (stiffened, compressed and splitting) and propose boundary conditions to investigate the impact of fibrosis on hemodynamic variables within the organ. We obtain that the sinusoids stiffness leads to changes in the amplitude and shape of the blood flow and pressure waveforms but not in their mean value. For the compressed and splitting sinusoids, we observe significant increases in the mean value and amplitude of the pressure waveform in the altered sinusoids and in the portal venous network. In other words, we obtain the portal hypertension clinically observed in fibrotic/cirrhotic patients. We also study the extent of the spreading fibrosis by performing the structural fibrotic changes in an increasingly number of sinusoids. Finally, we calculate the portal pressure gradient (PPG) in the model and obtain values in agreement with those reported in the literature for fibrotic/cirrhotic patients.

Polyautoimmunity manifest as inflammatory myopathy, uveitis, and progressive cutaneous depigmentation in a mixed breed dog: a case report

BackgroundPolyautoimmunity is the expression of more than one autoimmune disease in a single patient. This report documents polyautoimmunity in a mixed breed dog with concurrent uveitis, cutaneous depigmentation, and inflammatory myopathy.Case presentationA 1-year-old male neutered mixed breed dog was presented for progressive generalized leukotrichia and leukoderma, bilateral panuveitis, and masticatory muscle atrophy. The latter progressed to myositis of lingual, pharyngeal, and masticatory muscles confirmed by biopsy. Temporalis muscle was completely replaced by adipose and fibrous tissue, and necrotic myofibers with extensive infiltration of mononuclear cells indicated active myositis of lingual muscle. Skin biopsies showed severe melanin clumping in epidermis, hair follicles, and hair shafts, and perifollicular pigmentary incontinence. Uveitis, depigmentation, and myositis affecting the masticatory, pharyngeal, and tongue muscles were diagnosed based on clinical, histological, and laboratory findings.ConclusionsTo the authors’ knowledge, this is the first report of concurrent uveitis, progressive cutaneous depigmentation, and inflammatory myopathy in a dog.

A case of tuberculous pleurisy characterized by bleeding and necrosis documented by medical thoracoscope.

Tuberculous pleurisy is a main cause of pleural effusions. The main histological abnormalities in pleural biopsy of tuberculous pleurisy are caseating granulomas and epithelioid cell granuloma. In our case, chronic inflammation of fibrous tissue with bleeding, necrosis, and exudation were observed during a medical thoracoscopy as manifestations of tuberculous pleurisy.

Enzyme-linked immunosorbent assay and immunohistochemical analysis of mast cell related biochemicals in oral submucous fibrosis

Oral submucous fibrosis (OSMF), a potentially malignant disorder, is developed by progressive fibrous tissue deposition in connective tissue along with atrophy of oral mucosa. Histological sections also show the mast cell infiltration in submucosa which may indicate their possible role in this entity. Abundant availability of biochemicals in mast cells like histamine and serine proteases like chymase may be released and play specific pathways in the disease pathophysiology. Possibly, if the histamine release has some part to play, diamine oxidase may also be found to have a relationship as it metabolizes histamine. The present study is proposed to identify the presence of chymase, histamine, and diamine oxidase in both, serum as well as tissue by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) respectively. This study may provide probable insight into the mast cell-related chemicals and their association with OSMF.

Modified multi-Rayleigh model-based statistical analysis of ultrasound envelope for quantification of liver steatosis and fibrosis

PurposeQuantitative diagnosis of the degree of fibrosis progression is currently a focus of attention for fatty liver in nonalcoholic steatohepatitis (NASH). However, previous studies have focused on either lipid droplets or fibrotic tissue, and few have reported the evaluation of both in patients whose livers contain adipose and fibrous features. Our aim was to evaluate fibrosis tissue and lipid droplets in the liver.MethodsWe used an analytical method combining the multi-Rayleigh (MRA) model and a healthy liver structure filter (HLSF) as a technique for statistical analysis of the amplitude envelope to estimate fat and fibrotic volumes in clinical datasets with different degrees of fat and fibrosis progression.ResultsFat mass was estimated based on the non-MRA fraction corresponding to the signal characteristics of aggregated lipid droplets. Non-MRA fraction has a positive correlation with fat mass and is effective for detecting moderate and severe fatty livers. Progression of fibrosis was estimated using MRA parameters in combination with the HLSF. The proposed method was used to extract non-healthy areas with characteristics of fibrotic tissue. Fibrosis in early fatty liver suggested the possibility of evaluation. On the other hand, fat was identified as a factor that reduced the accuracy of estimating fibrosis progression in moderate and severe fatty livers.ConclusionThe proposed method was used to simultaneously evaluate fat mass and fibrosis progression in early fatty liver, suggesting the possibility of quantitative evaluation for discriminating between lipid droplets and fibrous tissue in the early fatty liver.

SAT194 A Rare Case Of Untreated Primary Hyperparathyroidism With Extremely High PTH And Lytic Bone Lesions

Abstract Disclosure: M. Shah: None. K. Akinola: None. M. Bollineni: None. S.A. Milan: None. S. Challagulla: None. Background: Primary hyperparathyroidism (PHPT) typically presents with PTH levels two times above the upper limit of normal. Given the increase in routine calcium measurements, PHPT is usually diagnosed and treated early and skeletal complications are not frequent at presentation. We present a case of PHPT with severely elevated PTH levels and bone lesions mimicking metastatic disease. Clinical Case: A 30-year-old male with a history of untreated primary hyperparathyroidism presented with severe chest wall pain and abdominal pain. Initial laboratory tests revealed a calcium level of 13.3 mg/dL (normal 8.6 to 10.5 mg/dL), alkaline phosphatase (AP) of 747 IU/L (normal 24 to 130 IU/L), and PTH of 2485 pg/mL (normal 9-77 pg/mL). The patient was diagnosed with primary hyperparathyroidism years before this presentation, but was lost to follow up due to lack of insurance. His PTH was first noted to be elevated in 2013 at 266 pg/mL. CT of the chest, abdomen, pelvis showed a 2.8 x 3.0 x 3.3 cm anterior mediastinal mass and diffuse mixed lytic and sclerotic bone lesions consistent with metastatic disease. The patient underwent further imaging with CT 4D parathyroid which revealed a 1.1 cm left inferior thyroid nodule and an anterior mediastinal mass of unclear etiology. Given the high concern for malignancy, a biopsy of the mediastinal mass was performed and returned as hypercellular parathyroid tissue with no atypia. Bone biopsies of the sclerotic lesions of the iliac crest were consistent with osseous tissue with prominent bone remodeling and fibrous tissue; no neoplasm was seen. He was treated with IV fluids and zoledronic acid during this work up which only temporarily improved his high calcium levels. He was then placed on cinacalcet prior to surgery. He ultimately underwent resection of the anterior mediastinal mass and left inferior parathyroid gland via a cervical approach. The patient’s preoperative PTH level was 3455 pg/mL and decreased to 209 pg/mL immediately after resection. Resection of the other parathyroid glands was not done due to the high risk of postoperative hypocalcemia. Pathology of both lesions returned as intrathymic parathyroid adenoma with focal fibrosis. Postoperatively, the patient developed symptomatic hypocalcemia as low as 6.4 mg/dL. He required IV and oral calcium for approximately 3 weeks postoperatively, consistent with hungry bone syndrome. He was discharged on an oral regimen of calcium supplementation. Discussion: Long standing untreated PHPT can present with severely elevated PTH levels and skeletal manifestations commonly mistaken for metastatic lesions. As in this case, parathyroidectomy was the only effective treatment. However, it can be complicated by hungry bone syndrome, especially in a patient with significant bone remodeling as evidenced by high AP and lytic bone lesions. Presentation: Saturday, June 17, 2023

THU452 Polyostotic Fibrous Dysplasia Complicated By Aneurysmal Bone Cyst In A Patient With McCune-Albright Syndrome

Abstract Disclosure: E. Milazzo: None. K.L. Hermayer: None. Introduction: McCune-Albright Syndrome (MAS) is a rare mosaic disorder with GNAS mutations, encoding the alpha-subunit of the Gs G-coupled protein receptor, activating it, and inappropriately producing cAMP. The hyperfunctioning endocrinopathies associated with MAS are due to signaling through the TSH, LH, FSH, GHRH, and ACTH receptors. MAS clinical presentation occurs with café-au-lait skin macules, precocious puberty, and fibrous dysplasia (FD) of the bone. FD is a benign tumor that leads to increased rates of bone fractures and if it causes facial deformities, can be complicated with orbital neuropathies. An aneurysmal bone cyst (ABC) is a blood-filled cyst that can be a primary or secondary lesion due to co-existing lesions. ABC is a rare complication of FD. We report a rare case of ABC in a MAS patient who presented with acute visual disturbance and enlargement of the forehead and was successfully treated with surgery. Clinical Case: A 20-year-old female diagnosed with MAS at the age of 2 who had precocious puberty by the 3rd year of life and developed polyostotic FD in the right arm, left femur, cranial, and skull bones with multiple long bone fractures by the age of 5-6 and required numerous orthopedic surgeries. She presented with the characteristic café-au-lait skin macules on the back and right arm. In 2018, a slow decline of left eye vision required left cranial decompression of the optic nerve, with pathology showing fibrous tissue compatible with FD. In 2021, she complained of acute right forehead enlargement, compressing her right eye with blurry vision. An MRI showed FD involving the facial and skull bones with a new expansible lesion in the right frontal bone with internal layering fluid, exerting a mild mass effect on the frontal lobe and extending superiorly to the orbit with inferior displacement of the globe. These findings were consistent with an ABC. Right frontal craniectomy and cranioplasty were performed in 12/2021, with pathology showing a fibrous pseudocyst wall with associated lymphoplasmacytic inflammation and evidence of prior hemorrhage with Ki-67 in the cyst wall at 15%. Lab work showed chronic alkaline phosphatase elevation at 567IU/L (42-106IU/L), normal calcium at 9.2mg/dl (8.4-10.3mg/dl), phosphate at 3.3mg/dl (3.3-5.1mg/dl), and PTH at 26pg/ml (15-65mg/dl), with Vitamin D insufficiency at 25.1ng/ml (30-100ng/ml). Endocrinology workup was negative for thyroid, adrenal, gonadotrophic, and GH dysfunction. 5 months post-surgery, the patient demonstrated complete recovery, and MRI showed no recurrence of the ABC. Conclusion: ABC is a benign solitary tumor generally arising from the metaphysis of long bones and rarely involves the cranium. ABC associated with FD has only been reported in a few cases. The treatment is surgical excision, with radiation and cryotherapy used in nonorbital cases. Presentation: Thursday, June 15, 2023

A histological study of the adult ligamentum arteriosum: Novel findings with application to a patent ductus arteriosus.

The ligamentum arteriosum (LA) is the vestigial fibrous remnant of the ductus arteriosus (DA), a fetal vessel arising from the left dorsal segment of the sixth aortic arch that connects the left pulmonary artery to the aortic arch. Incomplete obliteration of the DA results in a patent ductus arteriosus (PDA), causing the shunting of oxygen-rich blood to recirculate to the lungs, which can lead to pulmonary hypertension. The current study aims to further elucidate the structural characteristics of the LA via histological analysis with data gathered from adult cadaveric specimens. The LA was harvested and histologically observed with Hematoxylin and Eosin, van Gieson, and Masson's trichrome staining. Fibrous and muscle tissues were observed in all 25 specimens. The LA was categorized into three types based on the morphological features of the LA. Type I (vessel-like structure), type II (fibrotic tissue with duct-like structure), and type III (no duct-like structure) were found in 4.0%, 80.0%, and 16.0%, respectively. Finally, the remnant of a valve in the LA was also observed at the junction between the AA and LA. We suggest that this valve be called the "pulmonary-aortic valve." In the majority of the adult LAs, a duct-like structure was still present. These data could better elucidate our understanding of the pathology and etiology of a PDA.

Electron microscopic analysis of necrotic bone and failed implant surface in a patient with medication-related osteonecrosis of the jaw

BackgroundBisphosphonates (BP), a commonly used medication for various bone diseases, have been known to have severe complications such as bisphosphonate-related osteonecrosis of the jaw (BRONJ). Failure of dental implants has also been found in patients with medication-related osteonecrosis of the jaw (MRONJ). In this study, we analyzed the necrotic bone tissues and the surface of the failed implants removed from the jaw in patients treated with BPs and antiresorptive agents.ResultsChronic inflammatory cells with collagen and fibrous tissues and bone sequestrum were shown at 5.0 × , 10.0 × , 20.0 × , and 40.0 × magnified histologic sections in the bone and fibrotic scar tissues removed from patients with MRONJ due to osteonecrosis. Hardened bone tissues with microcracked bony resorbed lacunae were observed in SEM. Unlike the previously published comparative data where immune cells, such as dendritic cells, were found in the failed implant surface, these immune cells were not identified in the BRONJ-related peri-implantitis tissues through the TEM investigations. Furthermore, EDS revealed that in addition to the main titanium element, gold, carbon, oxygen, calcium, phosphorus, silicon, and sulfur elements were found.ConclusionHardened bone tissues with microcracked bony resorbed lacunae were observed in the SEM findings, which were considered as the main characteristic of the osteonecrosis of the jaw. Immune cells, such as dendritic cells were not identified in the TEM. EDS showed that in addition to the main titanium element, gold, carbon, oxygen, calcium, phosphorus, and silicon elements were found. Furthermore, it was revealed that sulfur was found, which was considered to be one of the complicated causes of implant failure in patients with BRONJ.