Giant Atrial Myxoma in a Pregnant Patient: A Case Report

Keywords
Myxoma; Heart Failure; Thoracic Surgery

Palavras-chave
Mixoma; Insuficiência Cardíaca; Cirurgia Torácica

Keywords
Myxoma; Heart Failure; Thoracic Surgery

Palavras-chave
Mixoma; Insuficiência Cardíaca; Cirurgia Torácica

Introduction

Atrial myxoma is the most prevalent primary heart tumor.¹,² Clinical manifestations of myxomas are usually nonspecific, and they may present with dyspnea, fatigue, reduced functional capacity, edema, and, eventually, cerebral embolic events with focal neurological deficits.³ Although they are classified as benign neoplasms, most commonly located in the left atrium, they can cause obstruction of intracardiac blood flow and, when friable, systemic embolism with consequent tissue ischemia.²,⁴

In spite of higher prevalence in women (65%), diagnosis during pregnancy is considered uncommon, with greater challenges in treatment and an increased risk of fetal death.⁵ We report the case of a pregnant patient with a complication of atrial myxoma that manifested during labor.

Case report

A 28-year-old primigravida female patient, who was previously healthy, received low-risk prenatal care in the obstetrics department of a tertiary hospital. Her blood pressure was normal at all appointments, and she used multivitamins and calcium supplements. At the end of the third trimester of pregnancy, she began to report a progressive increase in dyspnea and orthopnea, associated with lower limb edema, without relieving factors.

At gestational age consistent with 37 weeks and 2 days, she was admitted to a routine-risk maternity ward linked to a tertiary hospital, reporting worsening of the symptoms mentioned during prenatal care. Fetal vitality assessment was performed using cardiotocography, which showed signs indicative of fetal compromise, mainly due to fetal bradycardia. The patient was referred to the surgical center for a cesarean section, which proceeded without complications, except for a persistent cough throughout the surgery and bleeding in multiple tissue planes, requiring intraoperative administration of tranexamic acid.

Five hours after the procedure, she developed a seizure of unclear etiology, associated with oliguria and progressive dyspnea, requiring orotracheal intubation due to decreased level of consciousness. She also presented significant periorbital and lower limb edema. On the same day, she was referred to a secondary care hospital due to the unavailability of resources for adequate diagnosis and management at the maternity ward. The electrocardiograms performed did not show any noteworthy alterations. Transthoracic echocardiography identified the presence of a large mass in the left atrium, associated with right heart chamber overload, diffuse right ventricular hypokinesia, and pulmonary hypertension, with estimated pulmonary artery systolic pressure (PASP) of 91 mmHg. The patient was subsequently referred to a tertiary cardiology referral center and cardiac surgery due to suspected mechanical obstruction of blood flow through the mitral valve.

Following successful extubation, she underwent a new transthoracic echocardiogram, which revealed significant left atrial dilation (linear measurement of 47 mm, indexed volume of 62.2 mL/m²), with the presence of a large mobile mass in the left atrium, which projected into the mitral valve opening during diastole (Figure 1), associated with increased right ventricular dimensions (diastolic diameter of 45 mm), moderate systolic dysfunction, estimated PASP of 100 mmHg and borderline left ventricular systolic function (ejection fraction of 57%, using Simpson's method).

Figure 1
Transthoracic echocardiography in apical 4-chamber view. (A) Image suggestive of a mass in the left atrium (white arrow); (B) Image of the same mass projecting into the mitral valve orifice during diastole and occupying the left ventricle (blue arrow). LA: left atrium; LV: left ventricle; RA: right atrium; RV: right ventricle.

During hospitalization, the patient underwent surgical resection of the mobile mass identified on echocardiography. Through sternotomy and using cardiopulmonary bypass, a left atriotomy was performed with resection of the interatrial septum and identification of a 10-centimeter atrial myxoma (Figure 2) firmly adherent to the ostia of the right pulmonary veins, with a friable texture, which was resected with the right pulmonary vein and part of the left atrial wall. For complete resection, a right atriotomy with atrial septotomy was also necessary due to the extensive adherence of the myxoma. It was necessary to perform reconstruction of the interatrial septum, the left atrial wall, and the pulmonary veins, using a bovine pericardial patch. The procedure was completed without complications, and the surgical specimen was sent for histopathological analysis, which identified a myxoma measuring 10.0 × 8.6 × 3.3 cm and weighing 54 g, without associated malignant processes.

Figure 2
Surgical specimen of the atrial myxoma (yellow arrow).

Before hospital discharge, a postoperative follow-up transthoracic echocardiogram was performed, showing a significant reduction in PASP to 46 mmHg and preserved systolic and diastolic function in both ventricles. The patient was discharged from the hospital on the fourth postoperative day and remained asymptomatic during routine follow-up at the unit's outpatient clinic.

Discussion

Although the clinical picture is considered nonspecific, the symptoms of left atrial myxoma vary according to location, size, and mobility.⁶,⁷ In the reported case, the prolapse of the mass through the mitral valve orifice obstructed the left ventricular inflow tract and pulmonary venous return, raising filling pressures and triggering symptoms of cough and dyspnea, followed by acute pulmonary edema. An oligosymptomatic clinical course was likely misinterpreted as normal progression of pregnancy, with symptom exacerbation at the end of gestation and further worsening during and immediately after surgery.

The most commonly indicated treatment for clinically significant atrial myxomas is complete surgical resection, which presents excellent clinical outcomes and a low incidence of tumor recurrence, especially when accompanied by periodic echocardiographic monitoring.³,⁸,⁹ Various surgical techniques for left atrial myxoma resection, in addition to median sternotomy, have been described and are considered in different services, such as minimally invasive video-assisted surgery via minithoracotomy and right anterolateral minithoracotomy.⁸ However, in addition to being indicated in individualized situations, they require a higher level of specialization and availability of specific resources.

In order to ensure a complete surgical approach and better results, intraoperative transesophageal echocardiography is recommended, given that the main goals of surgery also include prevention of tumor recurrence. Risk factors associated with recurrence include incomplete resection, intracardiac implantation, embolization, and intraoperative displacement of tumor material. For this reason, a clear and comprehensive operative field should be considered, in addition to intraoperative echocardiography to confirm the absence of tumor residues.⁸

Pregnancy is a condition in which several modifications occur in the maternal organism in order to ensure optimal fetal development, such as increased cardiac output, increased blood volume, and reduced peripheral vascular resistance.¹⁰ Therefore, it is reasonable to consider whether the adaptations mentioned, especially maternal hypervolemia, may have contributed to our patient's clinical presentation. The hemodynamic changes at the end of pregnancy were added to those of the surgical trauma, culminating in a severe case of acute pulmonary edema, which required orotracheal intubation and initiated the urgent investigation of the cardiovascular abnormality.

We report a rare case of giant atrial myxoma in a pregnant patient, which manifested with typical symptoms of cardiac congestion and acute worsening after cesarean delivery, with a high risk of mortality. This highlights the importance of clinical reasoning and suspicion of possible differential diagnoses, especially given that, from an epidemiological perspective, atrial myxoma is rare during pregnancy, which can hinder diagnosis and delay appropriate treatment.

• Sources of Funding
  There were no external funding sources for this study.
• Study Association
  This study is not associated with any thesis or dissertation work.
• Ethics Approval and Consent to Participate
  This study received approval from the Ethics Committee of the Escola Superior de Ciências da Santa Casa de Misericórdia de Vitória (EMESCAM), under protocol number CAAE 93811125.0.0000.5065, opinion number 8.000.875. All procedures involved in this study were conducted in accordance with the 1975 Declaration of Helsinki, updated in 2013.
• Use of artificial intelligence
  The authors did not use any artificial intelligence tools in the development of this work.

Availability of Research Data

The underlying content of the research text is contained within the manuscript.

References

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Edited by

• Editor responsible for the review:
  Maria Otto

Publication Dates

• Publication in this collection
  20 July 2026
• Date of issue
  2026

History

• Received
  09 Feb 2026
• Reviewed
  29 Mar 2026
• Accepted
  29 Apr 2026