Resolving the heterogeneous tumour microenvironment in cardiac myxoma through single-cell and spatial transcriptomics

BACKGROUND

Cardiac myxoma (CM) is the most common (58%-80%) type of primary cardiac tumours. Currently, there is a need to develop medical therapies, especially for patients not physically suitable for surgeries. However, the mechanisms that shape the tumour microenvironment (TME) in CM remain largely unknown, which impedes the development of targeted therapies. Here, we aimed to dissect the TME in CM at single-cell and spatial resolution.

METHODS

We performed single-cell transcriptomic sequencing and Visium CytAssist spatial transcriptomic (ST) assays on tumour samples from patients with CM. A comprehensive analysis was performed, including unsupervised clustering, RNA velocity, clonal substructure inference of tumour cells and cell-cell communication.

RESULTS

Unsupervised clustering of 34 759 cells identified 12 clusters, which were assigned to endothelial cells (ECs), mesenchymal stroma cells (MSCs), and tumour-infiltrating immune cells. Myxoma tumour cells were found to encompass two closely related phenotypic states, namely, EC-like tumour cells (ETCs) and MSC-like tumour cells (MTCs). According to RNA velocity, our findings suggest that ETCs may be directly differentiated from MTCs. The immune microenvironment of CM was found to contain multiple factors that promote immune suppression and evasion, underscoring the potential of using immunotherapies as a treatment option. Hyperactive signals sent primarily by tumour cells were identified, such as MDK, HGF, chemerin, and GDF15 signalling. Finally, the ST assay uncovered spatial features of the subclusters, proximal cell-cell communication, and clonal evolution of myxoma tumour cells.

CONCLUSIONS

Our study presents the first comprehensive characterisation of the TME in CM at both single-cell and spatial resolution. Our study provides novel insight into the differentiation of myxoma tumour cells and advance our understanding of the TME in CM. Given the rarity of cardiac tumours, our study provides invaluable datasets and promotes the development of medical therapies for CM.

Carney complex predisposes to breast cancer: prospective study of 50 women

OBJECTIVE

Carney complex (CNC) is a rare genetic syndrome, mostly due to germline loss-of-function pathogenic variants in PRKAR1A. Carney complex includes pigmented skin lesions, cardiac myxomas, primary pigmented nodular adrenocortical dysplasia, and various breast benign tumors.

DESIGN

The present study was designed to describe the characteristics of breast lesions in CNC patients and their association with other manifestations of CNC and PRKAR1A genotype.

METHODS

A 3-year follow-up multicenter French prospective study of CNC patients included 50 women who were analyzed for CNC manifestations and particularly breast lesions, with breast imaging, genotyping, and hormonal settings.

RESULTS

Among the 38 women with breast imaging, 14 (39%) had breast lesions, half of them bilateral. Ten women (26%) presented with benign lesions and six with breast carcinomas (16%): one had ductal carcinoma in situ at 54, and five had invasive cancer before 50 years old, whom one with contralateral breast cancer during follow-up. The occurrence of breast cancer was more frequent in women with PRKAR1A pathogenic variant odds ratio = 6.34 (1.63-17.91) than in general population of same age. The mean age at breast cancer diagnosis was 44.7 years old: 17 years younger than in the general population. Breast cancer patients had good prognosis factors. All breast carcinomas occurred in individuals with familial CNC and PRKAR1A pathogenic variants. Loss of heterozygosity at the PRKAR1A locus in the 2 invasive breast carcinomas analyzed suggested a driver role of this tumor suppressor gene.

CONCLUSIONS

As CNC could predispose to breast carcinoma, an adequate screening strategy and follow-up should be discussed in affected women.

CLINICAL TRIAL REGISTRATION

ClinicalTrial.gov NCT00668291.

Genetic characterization of intramuscular myxomas

Introduction: Intramuscular myxomas are benign tumors that are challenging to diagnose, especially on core needle biopsies. Acquired chromosomal aberrations and pathogenic variants in codon 201 or codon 227 in GNAS complex locus gene (GNAS) have been reported in these tumors. Here we present our genetic findings in a series of 22 intramuscular myxomas. Materials and methods: The tumors were investigated for the presence of acquired chromosomal aberrations using G-banding and karyotyping. Pathogenic variants in codon 201 or codon 227 of GNAS were assessed using direct cycle Sanger sequencing and Ion AmpliSeq Cancer Hotspot Panel v2 methodologies. Results: Eleven tumors carried chromosomal abnormalities. Six tumors had numerical, four had structural, and one had both numerical and structural chromosomal aberrations. Gains of chromosomes 7 and 8 were the most common abnormalities being found in five and four tumors respectively. Pathogenic variants in GNAS were detected in 19 myxomas (86%) with both methodologies. The detected pathogenic variants were p.R201H in nine cases (seven with abnormal and two with normal karyotypes), p.R201C in five cases, all with normal karyotypes, p.R201S in three cases (two with abnormal and one with normal karyotype), p.R201G in one case with a normal karyotype, and p.Q227E in one case with a normal karyotype. Conclusion: Firstly, our data indicate a possible association between chromosomal abnormalities and GNAS pathogenic variants in intramuscular myxomas. Secondly, the presence of the rare pathogenic variants R201S, p.R201G and p.Q227E in 26% (5 out of 19) of myxomas with GNAS pathogenic variants shows that methodologies designed to detect only the common "hotspot" of p.R201C and p.R201H will give false negative results. Finally, a comparison between Ion AmpliSeq Cancer Hotspot Panel v2 and direct cycle Sanger sequencing showed that direct cycle Sanger sequencing provides a quick, reliable, and relatively cheap method to detect GNAS pathogenic variants, matching even the most cutting-edge sequencing methods.

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.

Recurrent multi-cameral cardiac myxomas in a child with Carney complex

Cardiac myxoma is a relatively rare tumour, usually solitary, that occurs primarily in the left atrium of adults, but comprises only 30% of cardiac tumours in children. We recently treated a 12-year-old girl with multiple recurrent myxomas in three cardiac chambers(following surgical resection 3 years earlier). Genomic analysis showed the PKAR1A mutation typical for Carney complex.

CTNNB1 and APC Mutations in Sinonasal Myxoma : Expanding the Spectrum of Tumors Driven By WNT/β-catenin Pathway

Sinonasal myxoma (SNM) is a rare, benign mesenchymal neoplasm with distinct clinicopathologic features and aberrant nuclear localization of β-catenin by immunohistochemistry. The molecular underpinnings have been linked to that of a "myxoid variant" of desmoid fibromatosis. Herein, we describe a series of 8 cases of SNM and propose clinical and biologic differences compared with desmoid fibromatosis. Our patient cohort is comprised of 5 males and 3 females (age range: 10 mo to 12 y), 6 of whom are aged less than or equal to 24 months. All presented with facial swelling, reflecting lesions involving the maxillary bone, and all underwent resection. All tumors were variably cellular and comprised of bland spindled to stellate cells in a profusely myxoid background with diffuse nuclear β-catenin expression. All cases of SNM were analyzed by next-generation sequencing using the Oncopanel assay. Three cases failed sequencing, 2 of 5 successful cases exhibited exon 3 CTNNB1 alterations involving the ubiquitin recognition motif, and 3 had adenomatous polyposis coli ( APC ) deletions. One patient had APC germline testing which was negative. No germline testing was available for the remaining 7 patients. Follow-up data over a range of 1 month to 23 years was available for 7 of the 8 SNMs. One case patient had local recurrence, and all were alive without evidence of disease. This is in contrast to the high recurrence rate typically seen in desmoid fibromatosis, particularly after resection. Our findings expand the spectrum of tumors with underlying WNT/β-catenin pathway and highlight the histologic, clinical, and genetic differences of SNM compared with desmoid fibromatosis. APC deletion raises the possibility of underlying germline alteration and familial adenomatous polyposis.

Whole genome sequencing resolves 10 years diagnostic odyssey in familiar myxoma

Carney complex (CNC) is an ultrarare disorder causing cutaneous and cardiac myxomas, primary pigmented nodular adrenocortical disease, hypophyseal adenoma, and gonadal tumours. Genetic alterations are often missed under routine genetic testing. Pathogenic variants in PRKAR1A are identified in most cases, while large exonic or chromosomal deletions have only been reported in a few cases. Our aim was to identify the causal genetic alteration in our kindred with a clinical diagnosis of CNC and prove its pathogenic role by functional investigation. Targeted testing of PRKAR1A gene, whole exome and whole genome sequencing (WGS) were performed in the proband, one clinically affected and one unaffected relative. WGS identified a novel, large, 10,662 bp (10.6 kbp; LRG_514t1:c.-10403_-7 + 265del; hg19, chr17:g.66498293_66508954del) deletion in the promoter of PRKAR1A in heterozygous form in the affected family members. The exact breakpoints and the increased enzyme activity in deletion carriers compared to wild type carrier were proved. Segregation analysis and functional evaluation of PKA activity confirmed the pathogenic role of this alteration. A novel deletion upstream of the PRKAR1A gene was proved to be the cause of CNC. Our study underlines the need for WGS in molecular genetic testing of patients with monogenic disorders where conventional genetic analysis fails.

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.

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.

A case report and literature review of Carney complex with atrial adenomyxoma

BACKGROUND

Carney complex (CNC) is a rare multiple endocrine neoplasia syndrome characterized by mucocutaneous lentigines/ blue nevi, cardiac myxoma and endocrine overactivity. Here, we report a CNC case with PRKAR1A gene mutation characterized by left atrial adenomyxoma to explore the diagnosis and treatment of CNC.

CASE PRESENTATION

A 42-year-old woman with a history of cardiac tumour surgery presented with typical features of Cushing syndrome, including central obesity, buffalo hump, mild facial plethora, purple striae on the lower abdomen, and spotty skin pigmentation. Left atrial adenomyxoma and thyroid papillary carcinoma were identified by postoperative histologic assays. Genetic screening revealed a pathogenic germline heterozygous mutation of c.682C > T (p.R228X) in exon 7 of the PRKAR1A gene. The clinical features and normal ACTH levels suggest this patient suffered the ACTH-independent primary pigmented nodular adrenocortical disease (PPNAD) with cyclic hypercortisolism or ACTH-dependent Cushing syndrome.

CONCLUSION

CNC is uncommon, however, if a patient develops clinical features involving multiple endocrine and non-endocrine tumors, especially Cushing syndrome and cardiac myxoma, CNC should be considered. Genetic analysis is recommended in patients with suspected CNC.

miRNAs in Cardiac Myxoma: New Pathologic Findings for Potential Therapeutic Opportunities

MicroRNAs (miRNAs) regulate gene expression at the post-transcriptional level, contributing to all major cellular processes. The importance of miRNAs in cardiac development, heart function, and valvular heart disease has been shown in recent years, and aberrant expression of miRNA has been reported in various malignancies, such as gastric cancer and breast cancer. Different from other fields of investigation, the role of miRNAs in cardiac tumors still remains difficult to interpret due to the scarcity publications and a lack of narrative focus on this topic. In this article, we summarize the available evidence on miRNAs and cardiac myxomas and propose new pathways for future research. miRNAs play a part in modifying the expression of cardiac transcription factors (miR-335-5p), increasing cell cycle trigger factors (miR-126-3p), interfering with ceramide synthesis (miR-320a), inducing apoptosis (miR-634 and miR-122), suppressing production of interleukins (miR-217), and reducing cell proliferation (miR-218). As such, they have complex and interconnected roles. At present, the study of the complete mechanistic control of miRNA remains a crucial issue, as proper understanding of signaling pathways is essential for the forecasting of therapeutic implications. Other types of cardiac tumors still lack adequate investigation with regard to miRNA. Further research should aim at investigating the causal relationship between different miRNAs and cell overgrowth, considering both myxoma and other histological types of cardiac tumors. We hope that this review will help in understanding this fascinating molecular approach.

Liver findings in patients with Carney complex, germline PRKAR1A pathogenic variants, and link to cardiac myxomas

This study aimed to evaluate liver involvement in patients with Carney complex (CNC) based on a large cohort and to analyze any germline PRKAR1A genotype-phenotype association of liver disease. The study included 83 patients with CNC, followed between 1995 and 2018 at a tertiary research center. We reviewed liver images, recorded types and number of lesions and analyzed per genotype: all patients were sequenced for the PRKAR1A gene. A total of 29/83 patients (24.0%) had liver radiological findings. Patients with liver lesion had a significantly higher rate of pathogenic variants detected in the PRKAR1A gene (72.4 vs 38.9%, P = 0.005, respectively). Patients with a pathogenic variant detected on germline PRKAR1A analysis had a higher risk for having a liver lesion compared with patients with wild-type (WT) PRKAR1A alleles (21/42 (50.0%) vs 8/41 (19.5%), respectively, P = 0.004). Among patients with liver lesions, those with a nonsense PRKAR1A pathogenic-variant had more liver lesions (7/7) than among those with other pathogenic-variant types (8/22, P = 0.001). In multivariable analysis, detection of liver lesion(s) was associated with an odds ratio of 5.2 for cardiac myxomas (95% CI 1.55-17.49, P = 0.008). In conclusion, patients with CNC, particularly with a PRKAR1A pathogenic variant, have a higher rate of liver lesions. Additionally, liver lesions are associated with a high risk for cardiac myxomas in this population.

Clonal Origin Patterns Play a Vital Role in Cardiac Myxoma Recurrence

OBJECTIVE

To explore the clonal origin pattern of cardiac myxoma and its relationship with recurrence of the disease.

METHODS

20 female patients diagnosed with cardiac myxoma underwent appropriate surgery and were followed-up after the treatment. The DNA of tumor tissues and pairing normal tissues from 20 patients were taken, with polymerase chain reaction (PCR) assay being used to amplify the HUMARA gene on X-chromosome, which could hint the tumor cloning state. Cases were divided into a polyclonal origin group and monoclonal origin group, according to the PCR result. The recurrence rate in the two groups was compared using Fisher's exact probability method.

RESULTS

All tumors were successfully removed. PCR assay showed that the hybrid rate in tumors was 90.0% (18/20). Among them, 88.9%(16/18) of cases were identified as polyclonal origin and 11.1%(2/18) were identified as monoclonal origin. After 4 years of follow-up, the recurrence rate was 12.5(2/16) in the polyclonal origin group and 0%(0/2) in monoclonal origin group, with significant difference between the two groups (P<0.05).

CONCLUSION

Cardiac myxoma is mostly of polyclonal original, and its polyclonal origin characteristics may contribute to tumor recurrence.

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.

Identification of a PRKAR1A mutation (c.491_492delTG) in familial cardiac myxoma: A case report

RATIONALE

Cardiac myxoma is the most common cardiac neoplasm. Currently, there are not many reports on familial cardiac myxoma. Herein, we reported 2 first-degree relatives with left atrial myxoma.

PATIENT CONCERNS

A 20-year-old female was admitted in our hospital for lapsing into a coma for 24 hours, and was diagnosed with recurrent left atrial cardiac myxoma. The patient's father also had a history of cardiac myxoma.

DIAGNOSIS

The patient was diagnosed with left atrial myxoma using transthoracic echocardiography (TTE). Whole exome sequencing (WES) identified a p.Val164Aspfs (c.491-492delTG) mutation in the cAMP-dependent protein kinase A (PKA) regulatory (R) subunit 1 (PRKAR1A) gene for both the proband and her father, but not in her uncle and brother, who had not shown manifestation of cardiac myxoma by the time of this report.

INTERVENTIONS

The myxoma resection was performed following the standard procedure of open chest surgery.

OUTCOMES

The tumor was successfully removed along with the tuberculum. The patient recovered well and was discharged home. No recurrence occurred during 1-year follow-up.

LESSONS

Our findings suggest that PRKAR1A mutation (c.491_492delTG) may be associated with cardiac myxoma, and genetic counseling and specific locus mutation tests may contribute to assessing the risk of cardiac myxoma.

Unusual presentations of Carney Complex in patient with a novel PRKAR1A mutation

Carney Complex (CNC) is a multiple neoplasia syndrome characterized by skin tumors and pigmented lesions, myxomas, and various endocrine tumors. The aim of this case report was to describe a case of CNC with a novel PRKAR1A mutation. A man aged 46 years with a medical history of surgery for cardiac myxomas at the age of 39 was admitted to our hospital because of four newly-developed heart masses. The histologic examination confirmed cardiac myxomas. He had many presentations of CNC such as growth hormone (GH) and prolactin (PRL)-secreting mixed pituitary adenoma, benign thyroid nodule, large-cell calcifying Sertoli cell tumor (LCCST), and superficial angiomyxoma. A bilateral adrenalectomy was performed because the laboratory findings suggested primary pigmented nodular adrenocortical disease (PPNAD). The pathologic examination revealed a focal unilateral PPNAD, unilateral nonpigmented adrenocortical nodule, and bilateral adrenal medullary hyperplasia. Two years after the second cardiac operation, an interatrial septum-derived tumor was detected. An atrial myxoma was confirmed with histologic studies. Based on these findings, the patient was confirmed to have CNC. A novel insertion mutation in the type 1A regulatory subunit of the cAMP-dependent protein kinase A gene (PRKAR1A) in exon 2 was detected in our patient through genetic analysis. The presence of multiple myxomas and endocrine abnormalities should be an indication to physicians to further investigate for CNC. Herein, we described a case of CNC with a novel mutation in exon 2 of the PRKAR1A gene with typical and atypical clinical features.

[Myxoid tumors of soft tissues]

Myxoid tumours of soft tissue represent a heterogeneous spectrum of lesions with variable biological behaviour, from completely benign to highly aggressive malignancies. Myxoid tumours share abundant myxoid extracellular matrix, overlapping histopathologic features and immunohistochemical findings, with resulting diagnostic problems. This review article attempts to give the most complete list possible, with the characterization of gross and microscopic features, relevant immunohistochemical and molecular biology findings and to outline differential diagnosis.

Mutation Analysis of PRKAR1A Gene in a Patient with Atrial Myxoma

BACKGROUND

Intracardiac myxomas are frequent benign tumors of the heart and typically localize in the left atri- um and interatrial septum. When myxomas generate at other sites, they are designated as atypical. Mutations in the PRKAR1A gene (a tumor suppressor gene that encodes a protein kinase A [PKA] regulatory 1-alpha subunit) have been identified in both syndromic and non-syndromic cardiac atypical myxomas.

METHODS

We report the case of a 33-year old woman suffering from night fever, weight loss, asthenia, and progressive dyspnea.

RESULTS

The blood laboratory tests revealed microcytic anemia, leukocytosis, thrombocytosis, increased serum levels of C-reactive protein level, and negative blood cultures. Physical examination also demonstrated a 2/6 systolic murmur. Transthoracic and trans-esophageal echocardiography showed a voluminous, mobile mass in the left atrium with a secondary dynamic obstruction of the left cardiac chamber and a significant functional mitral stenosis. A myxoma was supposed and the patient underwent surgery. Histologically, the lesion was identified as myxomatous tumor with gelatinous pattern. No germline mutations of the PRKAR1A gene were detected. The postoperative course did not present any complications, and the patient was discharged on the sixth postoperative day in good clinical condition. Accordingly, there was an improvement in the laboratory tests' results and a resolution of symptoms.

CONCLUSIONS

The patient presented an atrial giant gelatinous myxoma with peculiarity of fever of unknown origin, without PRKAR1A gene germline mutations.

The involvement of myocyte enhancer factor 2D in regulating tumor biology of cardiac myxoma

The pro-survival transcription factor myocyte enhancer factor 2D (MEF2D) is identified to exhibit pro-tumor effects based on clinical and experimental studies. However, the detailed mechanisms underlying IGF-1-MEF2D pathway-induced tumor biology in cardiac myxoma (CM) was not clear. Here, we investigated the role of MEF2D in CM tissues and cells using RT-PCR, western blot, gene silencing, et al. Our findings revealed MEF2D was significantly increased in CM tissues compared with adjacent normal tissues and closely related to tumor size. In vitro assay demonstrated that IGF-1 enhanced CM cell proliferation in a time-dependent fashion. However, knockdown of MEF2D reversed the IGF-1-induced proliferative effects on CM cells in a time-dependent fashion and further resulted in cell cycle arrest. Based on the molecular level, IGF-1 enhanced the expression of epidermal growth factor receptor (EGFR) and matrix metalloprotein 9 (MMP9) in CM cells, whereas knockdown of MEF2D was able to reduce the expression of EGFR and MMP9 compared with vector control. Furthermore, we found knockdown of MEF2D directly affected G1/S transition in cultured CM cells. In conclusion, MEF2D regulates IGF-1-induced proliferation and apoptosis in CM development, indicating IGF-1-MEF2D pathway may be a useful target for treatment.

Molecular basis of cardiac myxomas

Cardiac tumors are rare, and of these, primary cardiac tumors are even rarer. Metastatic cardiac tumors are about 100 times more common than the primary tumors. About 90% of primary cardiac tumors are benign, and of these the most common are cardiac myxomas. Approximately 12% of primary cardiac tumors are completely asymptomatic while others present with one or more signs and symptoms of the classical triad of hemodynamic changes due to intracardiac obstruction, embolism and nonspecific constitutional symptoms. Echocardiography is highly sensitive and specific in detecting cardiac tumors. Other helpful investigations are chest X-rays, magnetic resonance imaging and computerized tomography scan. Surgical excision is the treatment of choice for primary cardiac tumors and is usually associated with a good prognosis. This review article will focus on the general features of benign cardiac tumors with an emphasis on cardiac myxomas and their molecular basis.

Odontogenic myxomas are not associated with GNAS1 mutations

Myxomas are rare tumors of unknown aetiology arising in the jaws. Myxomas are also diagnosed in soft tissues. Recent reports on Gs alpha subunit gene (GNAS1) mutations occasionally being identified in soft tissue myxomas in non-syndromatic patients and the effects of myxoma on bone in variants of fibrous dysplasia led us to re-examine the putative role of GNAS1 mutations in odontogenic myxoma.

MATERIAL AND METHODS

Seven biopsies from patients with confirmed diagnosis of odontogenic myxoma and two cases of fibrous dyplasia of the jaw were investigated for GNAS1 mutations by polymerase chain reaction.

RESULTS

Although GNAS1 was mutated in cases of fibrous dysplasia, no GNAS1 mutations were detected in odontogenic myxomas.

CONCLUSION

The development of odontogenic myxoma is independent of mutations of GNAS1.

Clinical and molecular genetics of Carney complex

Carney complex (CNC) is a rare multiple familial neoplasia syndrome that is characterized by multiple types of skin tumors and pigmented lesions, endocrine neoplasms, myxomas and schwannomas and is inherited in an autosomal dominant manner. Clinical and pathologic diagnostic criteria are well established. Over 100 pathogenic variants in the regulatory subunit type 1A (RI-A) of the cAMP-dependent protein kinase (PRKAR1A) have been detected in approximately 60% of CNC patients, most leading to R1A haploinsufficiency. Other CNC-causing genes remain to be identified. Recent studies provided some genotype-phenotype correlations in CNC patients carrying PRKAR1A-inactivating mutations, which provide useful information for genetic counseling and/or prognosis; however, CNC remains a disease with significant clinical heterogeneity. Recent mouse and in vitro studies have shed light into how R1A haploinsufficiency causes tumors. PRKAR1A defects appear to be weak tumorigenic signals for most tissues; Wnt signaling activation and cell cycle dysregulation appear to be important mediators of the tumorigenic effect of a defective R1A.

Adrenal cortical tumors and multiple endocrine neoplasia-related syndromes

Relatively frequent, adrenal masses include a multitude of different tumor types: uni- or bilateral hyperplasias, adenomas, and the rare entity of adrenocortical carcinomas. With significant progress in our appreciation of their underlying molecular pathomechanisms and from analysis of affected individuals and their families, a number of inherited diseases and tumor syndromes have been linked to adrenocortical tumorigenesis. These syndromes and diseases include the Carney complex, the McCune-Albright syndrome, multiple endocrine neoplasia type 1, familial adenomatosis coli, congenital adrenal hyperplasia, familial forms of primary aldosteronism, the Beckwith-Wiedemann syndrome, and the Li-Fraumeni syndrome. The key to successful management of these syndromes is identification of patients harboring adrenal tumors within the context of hereditary diseases, since diagnostic procedures, therapy and follow-up may significantly differ from the management of sporadic, isolated adrenal tumors. This review explores the underlying genetic defects, diagnosis and therapy of the major heritable tumor syndromes associated with adrenocortical tumorigenesis.

Mutations in regulatory subunit type 1A of cyclic adenosine 5'-monophosphate-dependent protein kinase (PRKAR1A): phenotype analysis in 353 patients and 80 different genotypes

BACKGROUND

The "complex of myxomas, spotty skin pigmentation, and endocrine overactivity," or "Carney complex" (CNC), is caused by inactivating mutations of the regulatory subunit type 1A of the cAMP-dependent protein kinase (PRKAR1A) gene and as yet unknown defect(s) in other gene(s). Delineation of a genotype-phenotype correlation for CNC patients is essential for understanding PRKAR1A function and providing counseling and preventive care.

METHODS

A transatlantic consortium studied the molecular genotype and clinical phenotype of 353 patients (221 females and 132 males, age 34 +/- 19 yr) who carried a germline PRKAR1A mutation or were diagnosed with CNC and/or primary pigmented nodular adrenocortical disease.

RESULTS

A total of 258 patients (73%) carried 80 different PRKAR1A mutations; 114 (62%) of the index cases had a PRKAR1A mutation. Most PRKAR1A mutations (82%) led to lack of detectable mutant protein (nonexpressed mutations) because of nonsense mRNA mediated decay. Patients with a PRKAR1A mutation were more likely to have pigmented skin lesions, myxomas, and thyroid and gonadal tumors; they also presented earlier with these tumors. Primary pigmented nodular adrenocortical disease occurred earlier, was more frequent in females, and was the only manifestation of CNC with a gender predilection. Mutations located in exons were more often associated with acromegaly, myxomas, lentigines, and schwannomas, whereas the frequent c.491-492delTG mutation was commonly associated with lentigines, cardiac myxomas, and thyroid tumors. Overall, nonexpressed PRKAR1A mutations were associated with less severe disease.

CONCLUSION

CNC is genetically and clinically heterogeneous. Certain tumors are more frequent, with specific mutations providing some genotype-phenotype correlation for PRKAR1A mutations.

Analysis of GNAS1 and PRKAR1A gene mutations in human cardiac myxomas not associated with multiple endocrine disorders

Cardiac myxomas are rare tumors that usually occur as sporadic lesions or,more rarely, in the familial form,mostly in the context of Carney complex (CNC). The molecular basis for the development of cardiac myxomas is unclear. However, somatic activating mutations in the GNAS1 gene (the gsp oncogene) are detected in the myocardium ofMcCune-Albright syndrome patients while germ-line mutations in the PRKAR1A gene are associated with CNC and familial myxomas. We investigated the presence of activating missense mutations in the GNAS1 gene as well as of inactivating mutations in PRKAR1A in 29 sporadically occurring cardiac myxomas. No gsp and no PRKAR1A mutations were found by direct sequencing of PCR products amplified from tumoral DNA. This is the first study including a large series of sporadic, isolated cardiac myxomas and showing that these cardiac neoplasms do not share the same mutations found in familial forms.

The Carney complex gene PRKAR1A plays an essential role in cardiac development and myxomagenesis

Cardiac myxomas are the most common primary tumors of the heart, although little is known about their etiology. Mutations of the protein kinase A regulatory subunit gene PRKAR1A cause inherited myxomas in the setting of the Carney complex tumor syndrome, providing a possible window for understanding their pathogenesis. We recently reported that cardiac-specific knockout of this gene causes myxomatous changes in the heart, although the mice die during gestation from cardiac failure. In this review, we discuss these findings and place them in the larger understanding of how protein kinase A dysregulation might affect cardiac function and cause myxomagenesis.

Carney complex: a case report

Cardiac myxoma is the most common benign cardiac tumor, and 10% of cases are familial forms. The authors present a review of the literature on the Carney complex, and a case report of a 68-year-old man with a cardiac mass, associated with a significant family history and a diagnosis of coronary embolism.

[Cardiac myxomas and the Carney complex]

The study involved 63 patients with an echocardiographic, surgical and histopathologic diagnosis of cardiac myxoma who were seen over a period of 20 years. Tumor recurrence or relapse was documented in five of these patients (7.9%), 3 of whom had a confirmed diagnosis of Carney complex, while one other patient had a probable diagnosis. Genetic studies demonstrated abnormalities in the PRKAR1A gene on chromosome 17 in 2 patients and their immediate family. In 11 of the 58 patients who did not experience relapse of the myxoma, genetic studies failed to show any abnormality. In conclusion, the possible presence of the Carney complex should be investigated in patients with multiple myxomas or with a cardiac myxoma whose location is atypical.

Aggressive angiomyxoma with t(12;21) and HMGA2 rearrangement: report of a case and review of the literature

Conventional cytogenetic analysis of an aggressive angiomyxoma of the rectal wall of a 72-year-old woman revealed a translocation between the long arms of chromosomes 12 and 21, with the karyotype 46,XX,t(12;21)(q15;q21.1). Involvement of the HMGA2 gene locus (12q15) was confirmed by fluorescence in situ hybridization using an HMGA2 breakpoint flanking probe set performed on metaphase and interphase cells from an in situ culture of fresh lesional tissue. Karyotypic rearrangements of 12q13 approximately q15 are considered recurrent in aggressive angiomyxoma, although reported in only five previous cases. Translocation partner chromosome 21 is unique to the present case.

Male infertility as a component of Carney complex

Carney complex (CNC) is a multiple neoplasia syndrome characterised by endocrine tumours, spotty skin pigmentation, cardiac and other myxomas, psamommatous and pigmented schwannomas, large cell calcifying Sertoli cell tumours, and mammary ductal adenomas and other more rare lesions. CNC is inherited in an autosomal-dominant manner and has been mapped to at least two chromosomal loci. Patients who map to the CNC1 locus located on chromosome 17 carry inactivating mutations of the PRKAR1A gene that encodes the cAMP-dependent protein kinase regulatory subunit type 1-alpha (Kirschner et al., 2000). One gene responsible for type 2 (CNC2) is located on chromosome 2p16. Infertility in CNC can be caused by a number of factors; there is evidence that prkar1a deficiency in mice leads directly to infertility (Burton et al., 2006), but patients with CNC also have Sertoli cell tumours and a number of other reasons to affect fertility. We report on an infertile male with CNC and present evidence that male infertility should be considered as part of the phenotype of CNC.

Aggressive Angiomyxoma of the Vulva With a Sole t(5;8)(p15;q22) Chromosome Change

Aggressive angiomyxoma of the vulva is uncommon and the pathogenesis remains unclear. Recently, a few cytogenetic studies demonstrated chromosomal abnormalities in aggressive angiomyxoma of the vulva. A 45-year-old Japanese woman complaining of right-side vulva tumor measuring 3 cm in diameter was referred to our hospital. The mass was located at the right side of the rectovaginal septum and was closely adherent to the rectal serosa and the levator muscle ani. The tumor was completely resected. A pathological examination demonstrated aggressive angiomyxoma of the vulva. Chromosomal analysis of the tumor demonstrated a sole t(5;8)(p15;q22) translocation. This is the first case of an aggressive angiomyxoma of the vulva with a sole t(5;8)(p15;q22) translocation.

MIB-1, Bcl-2 and p53 in odontogenic myxomas of the jaws

Odontogenic myxoma is a rare benign neoplasm occurring in the jaws. Microscopically, it is composed of spindle or stellate-shaped cells arranged in a mucinous matrix. In some cases (20%), odontogenic epithelial islands may be found. The Authors evaluated p53, MIB-1, and Bcl-2 expressed by the epithelial and stromal elements in 12 cases of odontogenic myxoma of the jaws. The cells of the odontogenic epithelium were positive for Bcl-2, p53 and MIB-1. The stromal cell showed a high positivity for MIB-1. Proliferation of both the epithelial and stromal components could be related to the growth of this odontogenic tumour.

[Multiple myxomata: about one case]

Among the primitive cardiac tumours, myxoma is the most common. This benign tumour is sometimes described in the context of Carney's syndrome, in which cardiac myxoma, cutaneous myxoma, lentigo and pigmentary nevus cutaneous lesions, endocrine disorders, and testicular, thyroid and hypophyseal tumours are associated. The cardiac myxomata observed are multiple, recurrent, and involve the four cardiac chambers, with a peak incidence at 25 years of age. These observations may exist in a familial context, linked to an autosomal dominant genetic factor, localized on the 17q2 chromosome with polymorphism of the PRKAR1a gene. As in the case of sporadic myxoma, rapid surgical treatment with cardio-pulmonary bypass is indicated, bearing in mind the increased risk of thromboembolic phenomena and sudden death from valvular encroachment. We report a case of bi-atrial myxoma observed in the context of Carney's syndrome.

[Ocular findings in Carney complex]

CASE REPORT

Carney complex (CNC) is a multiple neoplasia syndrome, inherited in an autosomal dominant manner, characterized by myxomas, spotty skin pigmentation, endocrine tumors and ophthalmic abnormalities.

DISCUSSION

We report the ocular findings which usually precede the most serious component of the complex, the cardiac myxoma.

Primary pigmented nodular adrenocortical disease (PPNAD) and pituitary adenoma in a boy with sporadic Carney complex due to a novel, de novo paternal PRKAR1A mutation (R96X)

We report the sporadic case of a 9 year-old boy with Carney syndrome, who presented with precocious puberty due to the endocrinological effects of primary pigmented nodular adrenocortical disease (PPNAD) and a synchronous pituitary adenoma. The adrenal tumor was removed surgically. Following unsuccessful treatment with bromocriptine the pituitary adenoma was also resected and a residual tumor irradiated. Thirty months after diagnosis the boy is free of symptoms. Mutation screening of the entire coding region of the PRKAR1A gene identified five single nucleotide exchanges, four of which were either heterozygous or homozygous polymorphic variants that were also present in his parents. However, the hitherto unreported disease-relevant mutation R96X in exon 3 had occurred de novo on the paternal allele.

Fine-needle aspiration cytologic diagnosis of metastatic melanotic schwannoma: Familial case of a mother and daughter with Carney's complex and literature review

Carney's complex is an autosomal dominant, multisystem tumorous disorder that includes myxomas, spotty skin pigmentation, endocrine tumors, and peripheral nerve tumors. Psammomatous melanotic schwannomas have recently been included as a part of this complex. Here, we describe the first known familial case of a mother and daughter, both presenting with malignant, already metastatic, pigmented schwannomas initially diagnosed as metastatic melanoma by CT guided fine-needle aspiration. Patients with highly pigmented, extra-cutaneous lesions that are clinically and pathologically suspicious for metastatic malignant melanoma, without known primary tumor, should be evaluated for possible Carney's complex. Additional screening of family members should be recommended to exclude the presence of potentially malignant neoplasms, such as psammomatous melanotic schwannomas.

[Multiple recurrence of cardiac myxoma in a Carney complex patient 4 years after the first operation]

Carney complex is a rare syndrome which includes cardiac myxoma, hyperactive endocrine neoplasm, spotty pigmented skin, and extracardiac myxomatous tumors. We report a case of a 26-year-old woman with Carney complex in whom recurrent multiple cardiac myxomas were resected 4 years after the first operation for left atrial (LA) myxoma. She had a history of left adrenalectomy in 1997 for Cushing syndrome due to primary pigmented nodular adrenocortical disease (PPNAD). In February 2001, she was diagnosed with Carney complex because of evidence of LA myxoma, her spotty pigmented skin lesions, her past history and family history of cardiac myxoma in her mother. Then, LA myxoma was successfully resected through the superior trans-septal approach and has been followed-up by ultrasound cardiography (UCG) every 6-month after discharge. In January 2005, UCG revealed 2 masses in the LA and the right ventricle outflow tract. The 2nd surgery was performed in February 2005. We found the 3rd myxoma during surgery, resembling a flat polyp in the LA just at the inflow of the right upper pulmonary vein. All 3 myxomas were successfully resected. Sixteen months after the 2nd operation, she has been doing well without any sign of recurrence of myxoma.

HMGA2 rearrangement in a case of vulvar aggressive angiomyxoma

The histogenesis of aggressive angiomyxoma, an uncommon mesenchymal neoplasm of the vulvar, pelvic, and perineal soft tissues, is poorly understood, although the neoplastic cells exhibit a myofibroblastic phenotype. Cytogenetic studies of aggressive angiomyxoma are scarce; however, a nonrandom involvement of the 12q15 region where the high mobility group (HMG) protein HMGA2, an architectural transcription factor expressed primarily during embryogenesis, is located has been suggested. HMGA2 involvement has also been described in a variety of benign gynecologic mesenchymal neoplasms. We report an additional case of HMGA2 rearrangement in vulvar aggressive angiomyxoma, using fluorescence in situ hybridization.

Carney complex

We report an illustrated case of a 61-year-old woman with multiple atrial myxomas and cutaneous hyperpigmentation as part of the Carney complex. The case is notable for an unusually late presentation in life and a strong family history of atrial myxomas and sudden death. The importance of regular life-long echocardiographic screening and surveillance in all family members of affected cases is emphasized.

Carney complex (CNC)

The Carney complex (CNC) is a dominantly inherited syndrome characterized by spotty skin pigmentation, endocrine overactivity and myxomas. Skin pigmentation anomalies include lentigines and blue naevi. The most common endocrine gland manifestations are acromegaly, thyroid and testicular tumors, and adrenocorticotropic hormone (ACTH)-independent Cushing's syndrome due to primary pigmented nodular adrenocortical disease (PPNAD). PPNAD, a rare cause of Cushing's syndrome, is due to primary bilateral adrenal defect that can be also observed in some patients without other CNC manifestations or familial history of the disease. Myxomas can be observed in the heart, skin and breast. Cardiac myxomas can develop in any cardiac chamber and may be multiple. One of the putative CNC genes located on 17q22-24, (PRKAR1A), has been identified to encode the regulatory subunit (R1A) of protein kinase A. Heterozygous inactivating mutations of PRKAR1A were reported initially in 45 to 65 % of CNC index cases, and may be present in about 80 % of the CNC families presenting mainly with Cushing's syndrome. PRKAR1A is a key component of the cAMP signaling pathway that has been implicated in endocrine tumorigenesis and could, at least partly, function as a tumor suppressor gene. Genetic analysis should be proposed to all CNC index cases. Patients with CNC or with a genetic predisposition to CNC should have regular screening for manifestations of the disease. Clinical work-up for all the manifestations of CNC should be performed at least once a year in all patients and should start in infancy. Cardiac myxomas require surgical removal. Treatment of the other manifestations of CNC should be discussed and may include follow-up, surgery, or medical treatment depending on the location of the tumor, its size, the existence of clinical signs of tumor mass or hormonal excess, and the suspicion of malignancy. Bilateral adrenalectomy is the most common treatment for Cushing's syndrome due to PPNAD.

[Carney's Complex: familial cardiac myxoma]

The Carney Complex is a very rare autosomal dominant disease including multiple neoplasia syndrome. This syndrome was initially described in 1985 under the rubric "...the complex of myxomas, spotty pigmentation, and endocrine overactivity". We present a case report of an old woman with Carney Complex who had the characteristic features of facial hirsutism and acromegalic facies, a large pigmented swelling over the face and a cardiac myxoma arising from the left atrium. We emphasize the need for periodic echocardiographic screening of patients and family members.

Deregulation of HMGA2 in an aggressive angiomyxoma with t(11;12)(q23;q15)

Aggressive angiomyxoma is a soft-tissue neoplasm with a predilection for the pelvic and perineal regions and a tendency to recur locally. Cytogenetic data on this tumor type are limited to five cases, three of which showed rearrangement of chromosomal bands 12q13-15. Molecular investigation of two of the tumors identified the HMGA2 gene as the target of the 12q rearrangements. However, the two previously analyzed tumors were different at the molecular level: in one, the rearrangement of 12q13-15 resulted in a fusion product, whereas, in the second case, the breakpoint was telomeric (3') to the HMGA2, leaving the gene intact although expressed in its entire length. To shed more light on the pathobiology of aggressive angiomyxoma and to investigate the molecular mechanisms behind the involvement of the HMGA2 gene in this tumor type (fusion transcript vs deregulated expression), we investigated, cytogenetically and with molecular techniques, one such tumor which presented a t(11;12)(q23;q15) as the sole karyotypic aberration. FISH analyses demonstrated no structural alteration of HMGA2 at the cytogenetic level; however, expression of the full-length gene was detected molecularly.

Inherited disposition to cardiac myxoma development

Carney complex is a genetic condition in which affected individuals develop benign tumours in various tissues, including the heart. Most individuals with Carney complex have a mutation in the PRKAR1A gene, which encodes the regulatory R1alpha subunit of protein kinase A - a significant component of the cyclic-AMP signalling pathway. Genetically engineered mutant Prkar1a mouse models show an increased propensity to develop tumours, and have established a role for R1alpha in initiating tumour formation and, potentially, in maintaining cell proliferation. Ongoing investigations are exploring the intersection of R1alpha-dependent cell signalling with other gene products such as perinatal myosin, mutation of which can also cause cardiac myxomas.

Carney complex: pathology and molecular genetics

Carney complex (CNC) is a unique multiple endocrine neoplasia syndrome (MIM 160980) which is characterized by unusual biochemical features (chronic hypersomatotropinemia and paradoxical responses of cortisol production to glucocorticoids) and multi-tissue involvement. The gene coding for the protein kinase A (PKA) type 1alpha regulatory subunit, PRKAR1A, had been mapped to 17q22-24, one of the genetic loci involved in CNC, and allelic analysis using probes from this chromosomal region revealed consistent changes in CNC tumors. Sequencing of the PRKAR1A gene in over 100 kindreds showed a number of mutations; in almost all cases, the sequence change was predicted to lead to a premature stop codon, and mutant mRNAs were subject to nonsense-mediated mRNA decay. In CNC cells, PKA activity assays showed increased stimulation by cAMP. Few mutations that did not lead to a premature stop codon have been described; they are also associated with increased PKA activity. PRKAR1A has been investigated in sporadic endocrine tumors; it does not appear to be mutated in pituitary adenomas, but both thyroid and adrenal neoplasms have been found to harbor somatic mutations of this gene. Animal models of the disease have been developed. CNC is the first human disease caused by mutations of one of the subunits of the PKA holoenzyme, a critical component of numerous cellular signaling systems. This has wide implications for cAMP involvement in endocrine tumorigenesis.

Congenital dermatofibrosarcoma protuberans with fibrosarcomatous and myxoid change

This report describes a case of congenital dermatofibrosarcoma protuberans (DFSP) with fibrosarcomatous (FS) and myxoid areas. Immunohistochemical results showed that tumour cells in ordinary DFSP areas were diffusely positive for CD34, whereas in the FS and myxoid areas, few tumour cells were positive for this antigen. Ki-67 positive tumour cell numbers were greater in the FS (11.8%) and myxoid areas (19.8%) relative to ordinary DFSP areas (2.2%). Reverse transcription polymerase chain reaction and sequence analysis showed the presence of an identical COL1A1-PDGFB fusion transcript in ordinary DFSP (plaque-like area), FS, and myxoid areas of DFSP. These results indicate that the three components of DFSP have a common histogenesis. This study documents the first application of gene analysis involving the myxoid area of DFSP.

PRKAR1A gene mutation in patients with cardiac myxoma

BACKGROUND

PRKAR1A gene encodes the type 1A regulatory subunit of protein kinase A. The mutation of this gene causes Carney complex which is an autosomal dominant multiple neoplasia syndrome characterized by spotty pigmentations, endocrine overactivity and cardiac myxoma. We hypothesized that cardiac myxoma may be associated with PRKAR1A gene mutation and determined whether mutation in the PRKAR1A gene is the cause of familial and sporadic cardiac myxoma.

METHODS

We studied seven patients (three males and four females) with cardiac myxoma. Two of them had familial cardiac myxoma complicated with Carney complex. The other five patients were characterized as sporadic cardiac myxomas. We analyzed the PRKAR1A gene of all patients by the polymerase chain reaction (PCR)-single-strand conformation method, followed with direct sequence analysis.

RESULTS

We identified a novel mutation (494delTG) in exon 4A of the PRKAR1A gene in the patients with Carney complex. A 16-year-old proband had a left atrial myxoma, pituitary adenoma and skin pigmentation. His father also had left atrial myxoma and skin pigmentation. In contrast, no mutations in the PRKAR1A gene were identified in the other five patients with sporadic cardiac myxomas.

CONCLUSIONS

These results suggest that mutation of the PRKAR1A gene may be associated with familial cardiac myxoma in Carney complex but may not be associated with sporadic cardiac myxoma.

Genetic analysis in a patient with recurrent cardiac myxoma and endocrinopathy

A 60 year-old male was referred for treatment of a cardiac myxoma in the right atrium. He had a past history of left atrial cardiac myxoma at age 49 and pituitary microadenoma related to acromegaly at age 55. He did not have a family history of cardiac neoplasm or endocrinopathy. The intracardiac tumor was resected and its pathology was compatible with myxoma. A diagnosis of Carney complex (CNC) was made because the diagnostic criteria of this neoplastic syndrome were satisfied by the presence of recurrent cardiac myxoma, endocrine tumor and spotty skin pigmentation. In genetic analysis novel frame shift mutation was detected in exon 2 in a heterozygous fashion in the causative gene of CNC, protein kinase A regulatory subunit 1 alpha (PRKAR1A). This genetic mutation is thought to cause haplo-insufficiency of PRKAR1A resulting in tumorigenesis. Although it is the most common, usually benign, cardiac tumor, myxoma can cause a critical clinical situation and thus detecting the PRKAR1A mutation can assist with prognosis.