The Great Imposter: When a Heart Tumor Mimics a Serious Artery Disease
"Unraveling the Mystery of Left Atrial Myxoma and Polyarteritis Nodosa"
Vasculitis, a condition that impairs the function of tissues and organs due to inflammation of blood vessels, can be tricky to diagnose. While the Chapel Hill consensus provides criteria for classifying vasculitis, several other conditions can mimic its symptoms. These imposters include infections, cholesterol embolisms, fibromuscular dysplasia, and, surprisingly, a heart tumor known as atrial myxoma.
Atrial myxomas are non-cancerous tumors that typically grow in the left atrium of the heart. While benign, these tumors can cause a range of symptoms that overlap with those of vasculitis, leading to potential misdiagnosis. A recent case highlights this diagnostic challenge, involving a 32-year-old woman initially diagnosed with polyarteritis nodosa, who was later found to have a left atrial myxoma.
This article delves into the intriguing case of a heart tumor masquerading as a systemic vascular disease, shedding light on the importance of considering alternative diagnoses and employing comprehensive diagnostic approaches. We'll explore the symptoms, diagnostic process, and treatment strategies for both conditions, emphasizing the need for vigilance in differentiating between vasculitis and its mimics.
Recognizing Vasculitis Mimics
The cited source urges clinicians to remain alert to vasculitis mimics when managing patients with suspected vasculitis. It provides no statistics or figures about how often these mimics occur or their overall impact.
A Diagnostic Challenge
Atrial myxoma has been described as a mimic of systemic vasculitis, particularly when cardiac manifestations are absent, making diagnosis difficult. Diagnostic delay can lead to serious embolic complications, including stroke. A 2023 report describes a patient diagnosed with Carney complex after cardiac and cutaneous myxomas fulfilled two major diagnostic criteria. Intraoperative imaging showed a large myxoma arising from the secundum septum and a separate 8 mm sessile lesion on the left atrial free wall; both were excised.
The Case of the Mimicking Myxoma: A Diagnostic Puzzle
A 32-year-old woman sought medical attention, reporting fatigue, weakness, joint pain (arthralgia), muscle pain (myalgia), and a weight loss of 5 kg over six months. She was already taking metoprolol for hypertension. Her physical examination revealed a slightly elevated temperature (37.5°C), high blood pressure (160/100 mm Hg), and a pulse rate of 85 beats per minute. Doctors noted no neurological or cardiopulmonary abnormalities. However, she exhibited ischemia (reduced blood flow) in the second, third, and fourth digits of her right lower extremity.
- White blood cell count: 8600/mm³ (74% neutrophils)
- Hemoglobin: 10.7 g/dL
- Mean corpuscular volume: 81.9 fL
- Platelet count: 370000/mm³
- Erythrocyte sedimentation rate: 92 mm/hour
- C-reactive protein: 8.4 mg/dL
- Elevated liver enzymes: ALT (162 U/L), AST (53 U/L), alkaline phosphatase (94 U/L), GGT (63 U/L)
- Normal total bilirubin (0.2 mg/dL), total protein (7.7 g/dL), albumin (4 g/dL), and urea (58 mg/dL)
Recent Case Review
A case report published on November 30, 2024, describes a young man with a prior ischemic stroke who developed multiple ischemic insults in different territories while vasculitis was presumed. Further workup found a left atrial myxoma. The report notes that elevated erythrocyte sedimentation rate can occur with atrial myxoma, complicating efforts to distinguish it from central nervous system vasculitis. It identifies surgical resection as the standard treatment for atrial myxoma and says it can be curative.
Distinguishing Vasculitis from Its Mimics
A review of angiographic mimics of vasculitis lists atrial myxoma alongside amyloidosis, drug abuse involving agents such as ergot derivatives and sympathomimetics, Ehlers-Danlos syndrome, and exposure to cold or radiation. A separate review argues that greater awareness of vasculitis mimics can facilitate diagnosis and further study. It suggests that more reliable biomarkers, novel genetic markers, and advances in diagnostic imaging may improve the characterization of known mimics and help distinguish them from primary systemic vasculitides.
A Twist in the Tale: Unmasking the True Culprit
Despite treatment for polyarteritis nodosa, the patient continued to experience fatigue, weakness, and hypertension. These persistent symptoms prompted doctors to perform an echocardiography, which revealed a 3.2×2 cm mass in the left atrium. Further investigation and histopathological confirmation after surgical removal of the lesion led to the correct diagnosis: atrial myxoma. The steroid treatment was gradually reduced and eventually stopped. Additionally, magnetic resonance angiography ruled out vasculitis, revealing normal visceral arteries without aneurysms or occlusions.
Treatment Began under a Vasculitis Diagnosis
In the reported case of left atrial myxoma mimicking polyarteritis nodosa, clinicians initially diagnosed polyarteritis nodosa based on the clinical and laboratory findings. They began corticosteroid treatment at 1 mg/kg/day.
This case underscores the importance of considering alternative diagnoses when symptoms don't align perfectly with initial assessments. While immunosuppressive agents are standard for vasculitis, atrial myxomas require surgical intervention. Clinicians must remain vigilant about vasculitis mimics to ensure accurate diagnosis and appropriate treatment.
The patient continues to be monitored, showing normal inflammatory markers and remaining symptom-free. This case serves as a reminder that even with established diagnostic criteria, medical mysteries can arise, demanding a comprehensive and nuanced approach to patient care.