10× single-cell sequencing revealed cellular composition heterogeneity in cardiac myxoma with malignant glandular properties.

Cardiac myxoma is the most common primary cardiac tumor in adults. The histogenesis and cellular composition of myxoma are still unclear. This study aims to reveal the role of myxoma cell components and their gene expression in tumor development. We obtained single living cells by enzymatic digestion of tissues from 4 cases of surgically resected cardiac myxoma. Of course, there was 1 case of glandular myxoma and 3 cases of nonglandular myxoma. Then, 10× single-cell sequencing was performed. We identified 12 types and 11 types of cell populations in glandular myxoma and nonglandular myxoma, respectively. Heterogeneous epithelial cells are the main components of glandular myxoma. The similarities and differences in T cells in both glandular and nonglandular myxoma were analyzed by KEGG and GO. The most important finding was that there was active communication between T cells and epithelial cells. These results clarify the possible tissue occurrence and heterogeneity of cardiac myxoma and provide a theoretical basis and guidance for clinical diagnosis and treatment.

Autocrine Regulation of Interleukin-6 via the Activation of STAT3 and Akt in Cardiac Myxoma Cells.

Plasma concentrations of a pleiotropic cytokine, interleukin (IL)-6, are increased in patients with cardiac myxoma. We investigated the regulation of IL-6 in cardiac myxoma. Immunohistochemical staining and reverse transcription-polymerase chain reaction (RT-PCR) revealed that IL-6 and its receptors, IL-6 receptor (IL-6R) and gp130, co-existed in the myxoma cells. Myxoma cells were cultured, and an antibody array assay showed that a conditioned medium derived from the cultured myxoma cells contained increased amounts of IL-6. Signal transducer and activator of transcription (STAT) 3 and Akt were constitutively phosphorylated in the myxoma cells. An enzyme-linked immunosorbent assay (ELISA) showed that the myxoma cells spontaneously secreted IL-6 into the culture medium. Real-time PCR revealed that stimulation with IL-6 + soluble IL-6R (sIL6R) significantly increased IL-6 mRNA in the myxoma cells. Pharmacological inhibitors of STAT3 and Akt inhibited the IL-6 + sIL-6R-induced gene expression of IL-6 and the spontaneous secretion of IL-6. In addition, IL-6 + sIL-6R-induced translocation of phosphorylated STAT3 to the nucleus was also blocked by STAT3 inhibitors. This study has demonstrated that IL-6 increases its own production via STAT3 and Akt pathways in cardiac myxoma cells. Autocrine regulation of IL-6 may play an important role in the pathophysiology of patients with cardiac myxoma.

The benign nature and rare occurrence of cardiac myxoma as a possible consequence of the limited cardiac proliferative/ regenerative potential: a systematic review.

BACKGROUND: Cardiac Myxoma is a primary tumor of heart. Its origins, rarity of the occurrence of primary cardiac tumors and how it may be related to limited cardiac regenerative potential, are not yet entirely known. This study investigates the key cardiac genes/ transcription factors (TFs) and signaling pathways to understand these important questions. METHODS: Databases including PubMed, MEDLINE, and Google Scholar were searched for published articles without any date restrictions, involving cardiac myxoma, cardiac genes/TFs/signaling pathways and their roles in cardiogenesis, proliferation, differentiation, key interactions and tumorigenesis, with focus on cardiomyocytes. RESULTS: The cardiac genetic landscape is governed by a very tight control between proliferation and differentiation-related genes/TFs/pathways. Cardiac myxoma originates possibly as a consequence of dysregulations in the gene expression of differentiation regulators including Tbx5, GATA4, HAND1/2, MYOCD, HOPX, BMPs. Such dysregulations switch the expression of cardiomyocytes into progenitor-like state in cardiac myxoma development by dysregulating Isl1, Baf60 complex, Wnt, FGF, Notch, Mef2c and others. The Nkx2-5 and MSX2 contribute predominantly to both proliferation and differentiation of Cardiac Progenitor Cells (CPCs), may possibly serve roles based on the microenvironment and the direction of cell circuitry in cardiac tumorigenesis. The Nkx2-5 in cardiac myxoma may serve to limit progression of tumorigenesis as it has massive control over the proliferation of CPCs. The cardiac cell type-specific genetic programming plays governing role in controlling the tumorigenesis and regenerative potential. CONCLUSION: The cardiomyocytes have very limited proliferative and regenerative potential. They survive for long periods of time and tightly maintain the gene expression of differentiation genes such as Tbx5, GATA4 that interact with tumor suppressors (TS) and exert TS like effect. The total effect such gene expression exerts is responsible for the rare occurrence and benign nature of primary cardiac tumors. This prevents the progression of tumorigenesis. But this also limits the regenerative and proliferative potential of cardiomyocytes. Cardiac Myxoma develops as a consequence of dysregulations in these key genes which revert the cells towards progenitor-like state, hallmark of CM. The CM development in carney complex also signifies the role of TS in cardiac cells.

Crosstalk between KIF1C and PRKAR1A in left atrial myxoma.

Cardiac myxoma (CM) is the most common benign cardiac tumor, and most CMs are left atrial myxomas (LAMs). Six variations of KIF1C, c.899 A > T, c.772 T > G, c.352 A > T, c.2895 C > T, c.3049 G > A, and c.*442_*443dup in left atrial myxoma tissues are identified by whole-exome sequencing (WES) and Sanger sequencing. RNA-seq and function experiments show the reduction of the expression of KIF1C and PRKAR1A caused by rare variations of KIF1C. KIF1C is observed to be located in the nucleus, bind to the promoter region of PRKAR1A, and regulate its transcription. Reduction of KIF1C decreases PRKAR1A expression and activates the PKA, which causes an increase in ERK1/2 phosphorylation and SRC-mediated STAT3 activation, a reduction of CDH1, TP53, CDKN1A, and BAX, and eventually promotes tumor formation both in vitro and in vivo. The results suggest that inhibition of KIF1C promotes the pathogenesis of LAM through positive feedback formed by the crosstalk between KIF1C and PRKAR1A.

Superficial Angiomyxoma of the Wrist: Case Report and Literature Review.

BACKGROUND/AIM: Superficial angiomyxoma (SAM) is a rare benign soft-tissue tumor that usually occurs in the trunk, head and neck, and lower extremity of middle-aged adults. Herein, we describe an unusual case of SAM of the wrist, which was initially diagnosed as a ganglion cyst on imaging. CASE REPORT: The patient was a 71-year-old man with no history of trauma who presented with a 2-year history of a palpable mass in the left wrist. Physical examination revealed a 2.5-cm, elastic hard, mobile, nontender mass. Magnetic resonance imaging revealed a well-defined mass with iso-signal intensity relative to skeletal muscle on T1-weighted sequences and very high signal intensity on T2-weighted fat-suppressed sequences. Subtle internal enhancement was seen following gadolinium administration. Complete excision was performed under general anesthesia with tourniquet control. Histologically, the lesion was composed of bland spindle to stellate-shaped cells in an abundant myxoid stroma. Immunohistochemically, the lesional cells were positive for CD34 but negative for S-100 protein, smooth-muscle actin, desmin, epithelial membrane antigen and pancytokeratin. These findings were consistent with a diagnosis of SAM. There was no clinical evidence of recurrence during a follow-up period of 3 months. CONCLUSION: Although extremely rare, SAM should be considered in the differential diagnosis of a cyst-like solid lesion near small joints.

Somatic Mutation of PRKAR1A in Four Cases of Sporadic Cardiac Myxoma.

BACKGROUND: Inactivating mutations of the protein kinase A regulatory subunit 1 alpha (PRKAR1A) gene have been reported in familial cardiac myxoma. However, the role of PRKAR1A mutation in sporadic cardiac myxoma remains unknown. METHODS: Targeted next-generation sequencing (NGS) was performed to identify mutations with the PRKAR1A gene in seven cases of sporadic cardiac myxomas. Sanger sequencing of DNA from cardiac myxoma specimens and matched peripheral blood samples was performed to verify the identified mutations. RESULTS: Targeted NGS of myxoma DNA revealed 232 single nucleotide variants in 141 genes and 38 insertion-deletion mutations in 13 genes. Six PRKAR1A mutations were identified in four of the seven cardiac myxoma cases, and thus, the PRKAR1A inactivating mutation rate was 57.2% (4/7, 95% CI=0.44-0.58, P<0.05). The PRKAR1A variants identified by Sanger sequencing analysis were consistent with those from the NGS analysis for the four myxoma specimens. All of the pathogenic PRKAR1A mutations led to premature termination of PRKAR1A, except for one synonymous mutation. Moreover, none of the nonsense and missense mutations found in the myxoma specimens were found in the matched peripheral blood samples. CONCLUSION: Pathogenic mutations of the PRKAR1A gene were identified in tumor specimens from four cases of sporadic cardiac myxoma, and the absence of these mutations in peripheral blood samples demonstrated that they were somatic mutations.

Right atrial myxoma as the first manifestation of granulomatosis with polyangiitis, and a possible association with vascular endothelial growth factor (VEGF) and interleukin 6 (IL-6): a case report and review of the literature.

BACKGROUND: Granulomatosis with polyangiitis and myxomas are rare conditions previously described to co-exist. Cardiac masses are often presumed to be myxomas rather than lesions of granulomatosis with polyangiitis. CASE PRESENTATION: We present a review of the symptoms for the two diagnoses along with the first verified case. CONCLUSIONS: Two possible risk factors for developing myxomas (VEGF and IL-6) are explored and discussed.

Cerebral embolization associated with parenchymal seeding of the left atrial myxoma: Potential role of interleukin-6 and matrix metalloproteinases.

Systemic embolization has been reported in up to 40% of patients with left atrial myxoma, half of them with cerebral involvement. However, development of intracerebral embolization associated with parenchymal seeding of the myxoma emboli is an extremely rare complication, with only 36 histologically diagnosed cases reported in the published literature. We describe a 69-year-old woman who arrived at the emergency service with hemiparesis associated with drug-resistant epilepsy and a medical history of resection of a left atrial myxoma 10 months previously. Cranial computed tomography revealed multiple large lesions of heterogeneous density and cystic components in the occipital lobes and posterior fossa parenchyma. Histopathological analyses after stereotactic biopsy of the occipital lesion revealed infiltrative myxoma cells with benign histological findings and uniform expression of calretinin similar to that of the primary cardiac myxoma. Additional immunohistochemical studies confirmed brain parenchymal seeding of the myxoma cells with strong expression of interleukin-6 (IL-6) and focal expression of matrix metalloproteinases-2 (MMP-2). Here, we discuss the clinicopathological features of intracerebral embolization of left atrial myxomas associated with progressive parenchymal seeding of the tumor emboli and the potential pathogenic role of IL-6 and MMPs.

Hypermetabolic Cerebral Metastases of Cardiac Myxoma on FDG PET/CT.

ABSTRACT: A 66-year-old woman with a history of surgical resection of left atrial myxoma 6 months ago presented with multiple brain lesions with MRI. An FDG PET/CT was performed for further evaluation. The images showed that cerebral tumors had variable and increased FDG uptake in general, and no other abnormal FDG-avid lesions were noted. The tumor of right occipital lobe was resected and confirmed as metastatic cardiac myxoma on histology.

Cardiac Myxoma: Review and Update of Contemporary Immunohistochemical Markers and Molecular Pathology.

Cardiac myxoma is an uncommon benign mesenchymal neoplasm of the heart. It usually arises in the left atrium, near the valve of the fossa ovalis, and most frequently affects adults in the third through the sixth decades of life. It is hypothesized to arise from subendothelial vasoformative reserve cells or primitive cells that differentiate along the lines of the endothelium, but this remains speculative. Microscopically, the neoplastic cells are arranged individually, and nests, and are oriented in single or multiple layers around vascular channels. The neoplastic cells are immunoreactive for vimentin, calretinin, S100, nonspecific enolase, factor VIII, CD31, and CD34. The tumor can have diverse clinical presentations depending on its location and extent of disease and is predisposed to embolization. The current treatment is prompt surgical excision.

Aggressive angiomyxoma in pregnancy: a case report and literature review.

Aggressive angiomyxoma is an interstitial tumour that is often misdiagnosed and is likely to recur. There have been few reported cases of angiomyxoma in pregnant women. We report a case of a woman who was previously diagnosed with a tumour in her vulva that increased in size during both of her pregnancies and spontaneously decreased postpartum. Local excision was performed and a gonadotropin-releasing hormone agonist was administered. According to a literature review, aggressive angiomyxoma is associated with good maternal and child outcomes. Caesarean section is not the delivery method of choice, but it is indicated if the tumour is preventing vaginal birth. Treatment for angiomyxoma is mainly postpartum local resection supplemented by hormone therapy. This tumour frequently recurs and patients should undergo long-term follow-up.

The Biology of Myxofibrosarcoma: State of the Art and Future Perspectives.

BACKGROUND: Myxofibrosarcoma (MFS) is among the most highly complex sarcoma types. Molecular cytogenetic studies have identified a high level of genomic complexity. SUMMARY: This review provides an update of the current research related to MFS, with particular emphasis on emerging mechanisms of tumorigenesis and their potential therapeutic impact. Many novel possible molecular markers have been identified, not only for prognostication in MFS, but also to serve as possible therapeutic targets, and thereby improve clinical outcomes. However, the molecular pathogenesis of MFS remains incompletely understood. Key Messages: Patients suffering from advanced MFS might benefit from expanded molecular evaluation in order to detect specific expression profiles and identify drug-able targets. Moreover, immunotherapy represents an intriguingly perspective due to the presence of "T-cell inflamed" tumor microenvironment.

Early and delayed neurological manifestations of cardiac myxomas.

Cardiac myxoma can embolize and cause early and delayed sequelae including stroke, growth into intracranial fusiform aneurysms and cerebral tumors with risk of hemorrhage and mass effect. Here, we report the rare coincidence of all these manifestations in a 63-year-old man who presented with cognitive and behavioral changes, and seizures 9 months after an embolic stroke from the heart tumor. C-reactive protein (CRP) was elevated at the time of stroke and cardiac myxoma diagnosis but was normal at late neurologic manifestation with isolated myxoma-related intracranial tumors and aneurysms. Low-dose whole-brain radiotherapy can be helpful to diminish cerebral myxoma tumors and fusiform aneurysms despite reported increased risk of aneurysm rupture.

Next generation sequencing for GNAS uncovers CD34 as a sensitive marker for intramuscular myxoma.

BACKGROUND: Intramuscular myxoma is a soft tissue myxoid tumor with a broad morphological differential diagnosis and recent developments have led to the identification of markers that can exclude some, but not all, differential diagnostic entities. However, a sensitive confirmatory marker for intramuscular myxoma has not been clearly identified. Since there is some evidence that mutations in the GNAS gene could be such a marker, we evaluated our results of next-generation sequencing testing for GNAS mutations performed in recent years on our series of intramuscular myxoma. MATERIALS AND METHODS: Next-generation sequencing was performed on 10 cases of intramuscular myxoma diagnosed between 2015 and 2019, using either the TruSight Tumor 26 panel or an in-house developed 97 cancer gene panel. Additionally, immunohistochemistry for CD34 was performed on all cases. RESULTS: All intramuscular myxomas showed a diffuse and strong expression of CD34 and a GNAS mutation was found in 88% of cases, making this a very sensitive positive test for the diagnosis of intramuscular myxoma. CONCLUSIONS: Under the condition that contemporary next-generation sequencing is applied as testing method, searching for GNAS mutations is a very sensitive confirmatory test for the diagnosis of intramuscular myxoma, obviating the necessity to perform tests that exclude other entities by the virtue of their negative result. The molecular tests results also identified strong and diffuse CD34 expression as a sensitive, albeit non-specific, marker for intramuscular myxoma.

Conjunctival Myxoid Lesions: Clinical-Pathologic Multiparametric Analysis, Including Molecular Genetics (An American Ophthalmological Society Thesis).

PURPOSE: To evaluate the clinical and pathologic characteristics of conjunctival myxoid lesions, with specific focus on PRKAR1A studies, in order to distinguish neoplastic conjunctival myxoma from other myxoid conjunctival lesions. METHODS: A retrospective, interventional, multicenter study of all patients with conjunctival myxoma, conjunctival stromal tumor, or reactive fibromyxoid proliferation diagnosed during 1988-2018. Patient and family medical histories and clinical and pathologic characteristics of excised lesions were assessed. RESULTS: There were 28 patients with conjunctival myxoid lesions diagnosed as myxoma (16/28), conjunctival stromal tumor (10/28), or reactive fibromyxoid proliferation (2/28). The patients with abundant myxoid matrix lesions (14/28, 50%) were younger (mean 49 [range 23-68] years) than those with scant-to-moderate myxoid matrix lesions (14/28, mean 61 [range 18-82] years; P = .04). Abundant myxoid matrix lesions more likely contained predominantly stellate cells (6/14 [43%] vs 0/14 [0%]; P = .05) and fibrillar collagen (13/14 [93%] vs 2/14 [14%]; P < .0001), conforming to the standard morphologic definition of myxoma. Absence of PRKAR1A protein expression was found in 2 lesions with morphologic features of myxoma (2/14, 14%), 1 of which demonstrated a pathogenic mutation in the PRKAR1A gene. There was no difference between the lesions with respect to other clinical and pathologic parameters. CONCLUSIONS: PRKAR1A plays a role in the development of a subset of conjunctival myxomas, particularly in tumors fulfilling stringent morphologic criteria for myxoma. With the exception of PRKAR1A studies, current immunohistochemical panels cannot reliably distinguish between neoplastic conjunctival myxomas and other myxoid lesions, underscoring the importance of morphology in establishing accurate diagnosis.

Notch Signaling Affects Oral Neoplasm Cell Differentiation and Acquisition of Tumor-Specific Characteristics.

Histopathological findings of oral neoplasm cell differentiation and metaplasia suggest that tumor cells induce their own dedifferentiation and re-differentiation and may lead to the formation of tumor-specific histological features. Notch signaling is involved in the maintenance of tissue stem cell nature and regulation of differentiation and is responsible for the cytological regulation of cell fate, morphogenesis, and/or development. In our previous study, immunohistochemistry was used to examine Notch expression using cases of odontogenic tumors and pleomorphic adenoma as oral neoplasms. According to our results, Notch signaling was specifically associated with tumor cell differentiation and metaplastic cells of developmental tissues. Notch signaling was involved in the differentiation of the ductal epithelial cells of salivary gland tumors and ameloblast-like cells of odontogenic tumors. However, Notch signaling was also involved in squamous metaplasia, irrespective of the type of developmental tissue. In odontogenic tumors, Notch signaling was involved in epithelial-mesenchymal interactions and may be related to tumor development and tumorigenesis. This signaling may also be associated with the malignant transformation of ameloblastomas. Overall, Notch signaling appears to play a major role in the formation of the characteristic cellular composition and histological features of oral neoplasms, and this involvement has been reviewed here.

On-Tissue Hydrogel-Mediated Nondestructive Proteomic Characterization: Application to fr/fr and FFPE Tissues and Insights for Quantitative Proteomics Using a Case of Cardiac Myxoma.

PURPOSE: The application of a methodology for quantitative protein analysis from formalin-fixed and paraffin-embedded (FFPE) tissue by using hydrogels. Miniaturized polymeric gels are placed onto histologically defined tissue regions in order to perform localized digestion for bottom-up proteomics. Hydrogel-extracted peptides are then labeled with tandem mass tags (TMT) reagents for relative protein quantification. A cardiac myxoma biopsy is used. EXPERIMENTAL DESIGN: Multiple hydrogels, incorporating the proteolytic enzyme trypsin, are placed on serial tissue sections, and processed for digestion and TMT derivatization. SCX fractionation before LC-MS/MS analysis and bioinformatics analysis are carried out. RESULTS: Two histologically different areas on both FFPE and frozen sections of the same cardiac myxoma biopsy are compared. In total, 1949 (FFPE) and 2491 (frozen) proteins are identified, with a total overlap of 56%. The quantitative comparison highlighted 15 (FFPE) and 138 (frozen) differentially expressed proteins between myxoma regions. CONCLUSION: The methodology successfully detects numerous protein signals from FFPE and frozen specimens and is able to differentiate between tissue regions. A fast and reliable tissue preparation for quantitative protein analysis by minimum sample manipulation is developed. This offers an option for on-tissue proteomics analysis while preserving the inherent spatial information on the tissue.

Conjunctival myxoid stromal tumour: a distinctive clinicopathological and immunohistochemical study.

BACKGROUND/AIMS: To describe the clinicopathological and immunohistochemical characteristics of 10 patients representing a new entity of benign conjunctival myxoid stromal tumours. METHODS: Retrospective review of clinical findings, histopathological and immunohistochemical studies identified 10 cases of low-grade conjunctival myxoid stromal tumours. Specimens were routinely processed and stained with H&E. Immunohistochemical stains for CD34, CD68, vimentin, S100, smooth muscle actin (SMA), myosin, desmin, actin, Bcl-2 and Ki-67 were performed. Specific stains for Alcian-blue periodic acid-Schiff (AB-PAS) and aldehyde fuchsin stains were also performed. RESULTS: Ten patients with an average age of 45.6±11.1 years had a tender white or faint yellow to red mass on the bulbar conjunctiva. All the lesions were completely removed, and none of the patients relapsed. Histologically, all neoplasms consisted of spindle-shaped cells that showed signs of pseudonuclear inclusions, multinuclear cells and had no atypia. The stroma consisted of a large amount of mucus and was infiltrated with delicate to ropey collagens, a few mast cells and new vessels. Immunohistochemical stains were positive for CD34, vimentin and Bcl-2; partial positive for CD68; very low for Ki-67; and negative for S100, SMA, myosin, desmin and actin. AB-PAS suggested that the stroma was mucinous. CONCLUSIONS: These rare benign mesenchymal conjunctival tumours are mostly unilateral and occur in the bulbar conjunctiva. Complete resection is the radical treatment. These lesions are characterised by multiple spindle cells, a large amount of mucus, and sharing similar basic histopathological features with conjunctival myxoma and conjunctival stromal tumour. We suggest naming these lesions 'conjunctival myxoid stromal tumours'.

Evaluation and Immunolocalization of BMP4 and FGF8 in Odontogenic Cyst and Tumors.

Growth factors like bone morphogenetic protein 4 (BMP4) and fibroblast growth factor 8 (FGF8) play a major role in organogenesis and specifically in odontogenesis. They are also believed to have a role in oncogenesis. Thus, any discrepancies in their standard behavior and activity would lead to serious abnormalities including odontogenic cyst and tumors. The present research work investigated the expression of BMP4 and FGF8 in odontogenic tumors (OT) and cyst as well as developing tooth germs to elucidate their roles. Dental organs of various odontogenic stages and 30 OTs including solid multicystic ameloblastomas (SMA, 10 cases), ameloblastic fibroma (AF, 10 cases), odontogenic myxoma (OM, 10 cases), and odontogenic cysts: odontogenic keratocyst (OKC, 10 cases) were evaluated in both epithelial and mesenchymal components for the expression of BMP4 and FGF8 using immunohistochemistry. The epithelial nuclear expression of BMP4 was highest in OKC (9 cases) while FGF8 was highest in SMA (10 cases). The mesenchymal nuclear expression of both BMP4 (8 cases) (p = 0.001) and FGF8 (9 cases) (p = 0.045) were significantly high in OMs among all OTs. Both growth factors were actively expressed in different stages of tooth development. The expression of BMP4 and FGF8 corelates well with the proliferative component of the pathologies, indicating a possible role in the pathogenesis and progression.