Right atrial myxoma: unusual clinical presentation and atypical glandular histology

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.

[Cardiac myxoma: biological features, morphology, differential diagnosis]

Cardiac myxoma in its morphology is a typical benign tumor, meanwhile, the fact of its localization in the heart chamber, directly in the constant blood flow, largely determines the clinical behavior of this neoplasm, which is often manifested by the development of characteristics that formally determine the aggressive and even malignant nature of the course. Accordingly, the malignancy of cardiac myxoma is determined more by its clinical behavior (recurrence, multifocality of the lesion, the presence of mechanisms of spread similar to metastasis) rather than by its histological picture. In the structure of primary benign tumors of the heart, myxoma occupies a dominant position and its incidence is up to 85%. According to some authors, the tumor develops from multipotent mesenchymal stem cells of the endocardium, mainly in the area of the fossa ovale, while according to others the histogenesis of the tumor remains unclear. The obligate morphology element is the myxoma cell. The presence of so-called "ring" structures is special, regular and highly specific, and Gamna - Gandy bodies, foci of calcification and superficial thrombosis are considered characteristic secondary destructive morphological signs. The review describes the morphology features, specific clinical manifestations, immunohistochemical parameters of cardiac myxoma, and presents information available in the literature on the mechanisms of tumor spread (metastasis).

Giant right atrial myxoma presenting as right heart failure: a rare manifestation

A 37-year-old man was presented in outpatient clinic of cardiology department with symptoms of easy fatigability and progressive increasing generalised anasarca since 5 months. Echocardiogram showed large mass of 9.8×7.8 cm in size in right atrium, attached to interatrial septum. Urgent opinion of thoracic surgeon was taken and surgical excision of mass under cardiopulmonary bypass was done. The tumour was large, fragile and histology confirmed it as myxoma. The patient made a good recovery and his symptoms resolved completely on follow-up.

Massive right atrial myxoma presenting as congestive heart failure: an unusual presentation of a rare tumour

Cardiac myxomas are the most common type of primary cardiac tumour. The most common location of cardiac myxoma is left atrium. Right atrial myxomas are very rare and usually asymptomatic or sometimes present with dyspnoea. Right atrial myxoma presenting as a right-sided heart failure is very rare. We report a very rare case of a 52-year-old man of right atrial myxoma presented unsually as right-sided heart failure.

Identification of Stem-Like Cells in Atrial Myxoma by Markers CD44, CD19, and CD45

Atrial myxoma is the most frequent tumor arising mainly in atrial septum and its origin remains uncertain. It has been reported that a subpopulation of stem-like cells are present in benign tumors and responsible for tumor initiation and maintenance. In this study, we investigated whether stem-like cells could contribute to the atrial cardiac myxoma. Immunohistology data confirmed that a population of cells bearing the surface markers CD19, CD45, and CD44 resided in a mucopolysaccharide-rich matrix of myxoma. Moreover, we isolated myxoma cells with phase-bright culture method and confirmed that myxoma derived cells express robust level of CD19, CD45, and CD44. Furthermore, the pluripotency of this population of cells also was validated by cardiomyocytes and smooth muscle cells differentiation in vitro. Our results indicate that primary cardiac myxoma may arise from mesenchymal stem cells with the ability to generate tumors with multilineage differentiation. In conclusion, this study for the first time verified that stem-like cells are present in atrial myxoma and this population of cells may have the capacity for myxoma initiation and progression.

Large right atrial myxoma containing gastric heterotopia presenting with dyspnea and bilateral leg edema due to pulmonary emboli and cardiovascular obstruction: the first known report of gastric heterotopia in the cardiovascular system

A 52-year-old male presented with progressive dyspnea, bilateral leg edema, and elevated central venous pressure due to a large right atrial myxoma that caused vascular obstruction and pulmonary emboli. The myxoma contained gastric heterotopia. Other unusual features of this atrial myxoma included its large size, right atrial location, and attachment to the right atrial wall. Although gastric heterotopia has been reported throughout the gastrointestinal tract, and occasionally in other organs, this is the first report of gastric heterotopia in the cardiovascular system. This report confirms and extends previous reports of glandular elements or enteric glands within atrial, or cardiac, myxomas. The clinical presentation of the currently reported patient is explained as follows: the elevated central venous pressure resulted from cardiovascular obstruction and the dyspnea from multiple pulmonary emboli due to the large atrial myxoma. In this case, the clinical presentation was not attributable to the gastric heterotopia. The association of gastric heterotopia with atrial myxoma may, however, be clinically important because of the propensity of gastric heterotopia in the gastrointestinal tract to produce complications. The reported association may provide clues to the histogenesis of these two entities.

Left atrial myxoma diagnosed and characterized by cardiac magnetic resonance imaging

A 71 year old man was referred for MRI investigation of the heart. He had a history of progressive dyspnea. Due to his echocardiographical findings and the known history of permanent atrial fibrillation, his cardiologist suspected atrial thrombi. MRI investigation of the heart showed a left atrial mass pedunculated at the atrial septum which showed signal enhancement after intravenous administration of gadolinium-DTPA. Left atrial myxoma was suspected. The patient underwent surgery with resection of the tumor and patch-occlusion of the atrial septum. Histology confirmed a polypoid cardial myxoma.

Cardiac involvement in a case of acute lymphoblastic leukemia

We present an extremely rare case of an immunocompromised patient with a T-cell acute lymphocytic leukemia relapse presenting as a right atrial tumor. Problems in diagnosis, vulnerability due to previous immunosuppression and bone marrow transplant, and successful surgical excision are highlighted. Cardiac involvement with hematologic neoplasms should be taken with more than academic interest, as it may be amenable to treatment.

Pathology of surgically excised primary cardiac tumors

Between 1957 and March 1991, 106 patients with 110 neoplasms that originated in the heart were treated surgically at the Mayo Clinic and had pathologic material available for review. The study group consisted of 39 male and 67 female patients, who ranged in age from 2 to 80 years. Benign atrial myxomas (64 in the left atrium and 16 in the right atrium) were the most commonly encountered neoplasm. The other benign tumors were nine fibromas, five lipomatous tumors, seven valvular fibroelastic papillomas, and one cardiac hamartoma (so-called oncocytic cardiomyopathy). In addition, eight patients had a primary cardiac malignant lesion: angiosarcoma, leiomyosarcoma, and malignant fibrous histiocytoma in two patients each and sarcoma (not otherwise specified) and osteogenic sarcoma in one patient each. The angiosarcomas originated in the right atrium, and the other malignant tumors originated in the left atrium. The histologic feature that most frequently predicted an adverse clinical outcome was the presence of mitotic figures, although highly cellular tumors and those with necrosis also tended to have a malignant course.

Glandular cardiac myxomas. Histologic, immunohistochemical, and ultrastructural evidence of epithelial differentiation

Histologic, histochemical, immunocytochemical, and ultrastructural features of two cardiac myxomas containing glandular elements are reported. Glandular elements in both cases stained positively with both mucicarmine and periodic acid-Schiff reagent with diastase pretreatment (DPAS). Immunoperoxidase studies demonstrated positivity of the glandular cells for carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), and keratin. Factor VIII-related antigen (FVIIIAg) was identified only in cells lining vascular spaces. Electron microscopic study of one tumor demonstrated well-formed glands having basement membranes, junctional complexes, and apical secretory granules. These findings indicate the capacity for true epithelial differentiation of cardiac myxomas and have implications both as regards the histologic diagnosis of these tumors and their histogenesis.

Hematologic manifestations and etiology of atrial myxoma

We have investigated the case of a woman, 44 years of age, who presented with erythrocytosis, thrombocytopenia and a right axial myxoma. Surgical removal of the tumor allowed correction of all hematologic abnormalities. A serum erythropoietin level obtained from the right atrium of the patient during pre-operative cardiac catheterization was twice those of 4 control patients (250 MIU vs. 131 MIU). Renal vein erythropoietin levels were normal. This implicates atrial myxomas as another tumor capable of erythropoietin production, and explains the heretofore mysterious polycythemia frequently reported to be associated with this tumor.