Abstract
Background
Lung carcinoma is a leading cause of cancer-related mortality globally. Although metastasis to the bone, brain, and adrenal glands is common, secondary cardiac involvement is exceptionally rare, particularly within the left atrium.
Case Presentation
A 62-year-old female patient, a known case of hypothyroidism, presented with a 6-month history of class II dyspnea on exertion and easy fatigability. She also reported a 2-month history of giddiness, chest discomfort, and weight loss. Initial 2-dimensional echocardiography revealed a large left atrial mass, suspected to be a tumor thrombus. Subsequent diagnostic evaluations, including a chest computed tomography scan and positron emission tomography, identified a primary lung carcinoma. A bronchoscopic biopsy confirmed poorly differentiated nonsmall cell lung cancer.
Conclusions
This case highlights the importance of integrating multimodal imaging to accurately diagnose atypical intracardiac masses. It also emphasizes the clinical necessity of including metastatic lung malignancy in the differential diagnosis when an intracavitary cardiac mass is discovered.
Key words: cancer, cardiovascular disease, nuclear medicine
Visual Summary
Lung cancer remains the most frequently diagnosed malignancy and the leading cause of cancer-related deaths worldwide.1 Although nonsmall cell lung cancer commonly metastasizes to organs such as the liver, bone, brain, and adrenal glands, metastatic spread to the heart is considered exceptionally rare.2 The reported incidence of cardiac metastasis among lung cancer patients ranges from 1.8% to 3.1%.2 When cardiac metastases do occur, they predominantly involve the pericardium or epicardium; direct intracavitary involvement, such as metastasis localizing as a mass within the left atrium or the ventricular cavities, is the rarest form of presentation.3,4 We report an unusual presentation of poorly differentiated lung carcinoma masquerading as a large left atrial mass.
History of Presentation
A 62-year-old female patient was admitted with a 6-month history of progressive dyspnea on exertion (NYHA functional class II) and easy fatigability with intermittent fever. Her symptoms had worsened over the past 2 months, accompanied by new-onset giddiness, chest discomfort, and significant weight loss. Physical examination on admission revealed normal blood pressure (120/78 mm Hg), sinus tachycardia (pulse rate 104 beats/min), and normal oxygen saturation on room air without signs of overt heart failure or neurological deficits.
Past Medical History
She is a known case of primary hypothyroidism maintained on thyroid hormone replacement therapy. Family history was notable only for a brother who deceased from carcinoma; no other significant familial conditions were reported.
Differential Diagnosis
Given the echocardiographic finding of a large intracavitary left atrial mass, the principal differential diagnosis included benign primary cardiac tumors (predominantly left atrial myxoma), atrial thrombus, infective endocarditis vegetation, or secondary metastatic malignancy.
Investigations
An extensive cardiopulmonary evaluation was conducted. A 2-dimensional echocardiography revealed a large mass located in the left atrium (Figure 1). However, the echocardiographic appearance was atypical for myxomas.
Figure 1.
Transthoracic 2-Dimensional Echocardiography Demonstrating a Large, Atypically Appearing Mass Located Within the Left Atrial Cavity
To further investigate the mass and evaluate the patient's systemic symptoms (such as weight loss and fever), a computed tomography (CT) scan of the chest was performed. The CT imaging definitively identified a primary lung carcinoma (Figure 2). For comprehensive systemic staging, a whole-body positron emission tomography scan was subsequently conducted and found to be supportive, revealing a metabolically active disease mass involving the perihilar and suprahilar region of the left lung, infiltrating into the left superior pulmonary vein and extending up to the left atrium (Figure 3, Video 1). Finally, to secure a tissue diagnosis, the patient underwent a bronchoscopic biopsy of the lung lesion (Figure 4, Video 2). The histopathological examination of the biopsied tissue conclusively demonstrated a poorly differentiated nonsmall cell lung carcinoma (NSCLC) (Figure 5).
Figure 2.
Computed Tomography Scan of the Chest Demonstrating the Presence of a Primary Lung Carcinoma Lesion
Figure 3.
Whole-Body Positron Emission Tomography Scan Demonstrating a Hypermetabolic Disease Mass Involving the Perihilar and Suprahilar Regions of the Left Lung, Directly Tracking Along and Infiltrating the Left Superior Pulmonary Vein to Enter the Left Atrium
Figure 4.
Bronchoscopic Visualization and Targeted Tissue Biopsy of the Primary Left Lung Lesion
Figure 5.
Histopathological Analysis of the Bronchoscopic Biopsy Tissue, Conclusively Confirming Poorly Differentiated Nonsmall Cell Lung Carcinoma
Histopathological examination of the bronchoscopic biopsy specimen demonstrating tumor tissue composed of large pleomorphic cells with moderate cytoplasm and hyperchromatic nuclei (yellow arrow), featuring a moderate degree of nuclear. pleomorphism and atypia with occasional atypical mitoses, consistent with poorly differentiated nonsmall cell lung carcinoma.
Management
The presence of intracavitary cardiac metastasis is indicative of advanced-stage, unresectable disease (stage IV).5 Because patients with cardiac metastases frequently present with a significant systemic tumor burden, systemic therapy is considered the definitive treatment modality.6 Depending on the patient's performance status, hemodynamic stability, and molecular profiling of the tumor, treatment pathways generally involve a multidisciplinary integration of systemic options such as platinum-based chemotherapy, targeted therapies, or immunotherapy.
Following the bronchoscopic biopsy confirming poorly differentiated NSCLC, the clinical team discussed the imperative need for immunohistochemistry (IHC) subtyping and molecular profiling to determine eligibility for targeted therapies, platinum-based chemotherapy, or immune checkpoint inhibitors. However, after a thorough multidisciplinary counseling session regarding the advanced systemic tumor burden, anticipated cardiotoxicities of therapies, and overall prognosis, the patient and family electively declined further diagnostic IHC workup and active oncological management. The therapeutic strategy was subsequently shifted entirely to optimization of primary hypothyroidism, strict palliative monitoring, and symptomatic comfort care.
Outcome and Follow-Up
Due to the elective refusal of systemic oncological therapies, the patient was managed conservatively within a palliative framework with a focus on quality of life and noninvasive symptom control without exposure to systemic adverse effects or therapy-related cardiotoxicities.
Discussion
Lung cancer metastasis directly presenting as a large intracavitary left atrial mass is highly atypical. Most often, primary cardiac tumors are benign (such as myxomas), whereas metastatic cardiac tumors are up to 20-30 times more frequent than primary malignant cardiac tumors.3,7 The clinical manifestations of cardiac metastases are notoriously nonspecific and variable, ranging from paraneoplastic syndromes and dyspnea to more constitutional symptoms such as weight loss and fatigue. In this case, the patient's symptoms of dyspnea, chest discomfort, weight loss, and fever perfectly align with the varied clinical picture of intracardiac malignancy.
This case underscores the diagnostic complexities associated with intracardiac masses. Transthoracic echocardiography is essential for initial detection, but its ability to differentiate between a thrombus, an endocarditis vegetation, a primary tumor, and a secondary metastasis is limited. Therefore, the incorporation of multimodal imaging is highly recommended. As demonstrated in this case, the use of CT and positron emission tomography scans was vital in identifying the occult primary lung malignancy and correctly staging the disease.8
Managing advanced stage IV NSCLC with secondary cardiac involvement demands a complex balance between therapeutic efficacy and safety.9 If active therapy is initiated, clinicians must maintain strict vigilance for anticipated therapy-induced cardiotoxicities. Platinum-based regimens carry an inherent risk of thromboembolic events, which can be compounding the embolic potential of an existing left atrial tumor.5 Furthermore, modern immunotherapies are heavily associated with immune-related adverse events, including fulminant myocarditis, pericarditis, and conduction blocks.10 When an aggressive tumor burden is already localized inside a cardiac chamber, underlying myocardial reserve may be heavily compromised, making active cardiotoxicity monitoring via sequential cardiac biomarkers and echocardiography essential.
Conclusions
The discovery of a massive left atrial tumor masquerading as a thrombus in a patient with a poorly differentiated lung carcinoma is a rare clinical occurrence. This case illustrates the critical imperative for clinicians to maintain a high index of suspicion for metastatic disease when evaluating an unusual intracavitary mass, particularly in older patients with systemic symptoms like weight loss. Prompt implementation of multimodal imaging and tissue biopsy is essential to ascertain a definitive diagnosis and expedite the initiation of systemic multidisciplinary treatment.
Visual Summary.
A Comprehensive Diagnostic Timeline and Multimodal Imaging Schematic Tracking the Initial Clinical Presentation of an Atypical Left Atrial Mass, Leading to the Definitive Diagnosis of Primary Poorly Differentiated Nonsmall Cell Lung Carcinoma (NSCLC)
IHCC = intrahepatic cholangiocarcinoma; PET = positron emission tomography.
Funding Support and Author Disclosures
The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
Take-Home Messages
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Secondary metastatic lung malignancy must be considered in the differential diagnosis of atypical intracavitary left atrial masses, as direct invasion along the pulmonary veins can closely mimic primary benign cardiac tumors or thrombi.
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Early implementation of multimodal imaging (combining echocardiography, computed tomography, and positron emission tomography) is essential to delineate tumor extension, identify the primary pulmonary origin, and safely guide clinical management strategies.
Footnotes
The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the Author Center.
Appendix
For supplemental videos, please see the online version of this paper.
Appendix
Positron Emission
Tomography Scan Demonstrating a Metabolically Active Disease Mass Involving the Perihilar and Suprahilar Regions of the Left Lung, Showing Active Infiltration into the Left Superior Pulmonary Vein and Extension Directly Into the Left Atrium
Bronchoscopic Evaluation Tracking the Internal Anatomy and Revealing the Poorly Differentiated Primary Lung Carcinoma Lesion
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Associated Data
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Supplementary Materials
Positron Emission
Tomography Scan Demonstrating a Metabolically Active Disease Mass Involving the Perihilar and Suprahilar Regions of the Left Lung, Showing Active Infiltration into the Left Superior Pulmonary Vein and Extension Directly Into the Left Atrium
Bronchoscopic Evaluation Tracking the Internal Anatomy and Revealing the Poorly Differentiated Primary Lung Carcinoma Lesion