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\begin{document}

\title{Cardio-Invasive Metastatic Squamous Cell Carcinoma of the Lung
Masquerading as Acute ST Elevation Myocardial Infarction}



\author[1]{Nihar Jena}%
\author[2]{Shreya Tiwary}%
\author[3]{Deepak Chandramohan}%
\author[4]{SREEKANT AVULA}%
\author[5]{Prashanth Reddy}%
\author[6]{Harkesh Arora}%
\author[1]{Geetha Krishnamoorthy}%
\author[1]{Kirit Patel}%
\author[7]{Aiden Abidov}%
\affil[1]{Trinity Health Oakland Hospital}%
\affil[2]{Sparrow/Michigan State University Family Medicine Residency Program}%
\affil[3]{University of alabama at Birmingham}%
\affil[4]{University of Minnesota Twin Cities}%
\affil[5]{Yuma Regional Medical Center}%
\affil[6]{Lovelace Health System}%
\affil[7]{Wayne State University School of Medicine}%


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  \date{May 26, 2024}


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\textbf{Introduction:}

Myocardial metastatic cancer is rare, and diagnosis is challenging.
Supradiaphragmatic malignancies are the most common to metastasize to
the heart. Endocardial involvement is rare, followed by involvement of
the pericardium, epicardium, and myocardium. Myocardial metastasis leads
to varied clinical presentations ranging from arrhythmias, congestive
heart failure, myocardial infarction, and intracavitary mass lesions
(1). We are describing a patient with a prior diagnosis of coronary
artery disease (CAD) and Coronary artery bypass graft (CABG) presenting
as recurrent ST-elevation myocardial infarction (STEMI) and diagnosed
with cardiac metastasis from lung squamous cell carcinoma (SCC).

\textbf{History:}

A 63-year-old with a history of CAD and CABG presented from cardiac
rehabilitation (CR) with acute onset chest pain and shortness of breath.
The patient underwent CR after an acute myocardial infarction one week
ago. During that time, he had a similar presentation with chest pain and
dyspnea and was diagnosed with anteroseptal STEMI. Emergent percutaneous
coronary intervention (PCI) revealed severe stable CAD with patent left
internal mammary artery to left anterior descending artery (LAD),
Saphenous vein grafts (SVG) to obtuse marginal, SVG to the diagonal
artery, and occluded SVG to right coronary artery (RCA). Considering the
ongoing symptoms, a large septal branch was revascularized. The patient
became symptom-free, and ECG normalized. Following his discharge at CR,
he experienced similar symptoms and was sent to the emergency department
for further evaluation.

\textbf{Past medical history:}

The patient had a medical history of CAD with CABG, peripheral arterial
disease with multiple interventions, paroxysmal atrial flutter,
hypertension, dyslipidemia, diabetes mellitus type 2, deep vein
thrombosis, and ischemic stroke with residual aphasia. The patient had a
lung cancer screening with low-dose CT a year ago without suspicion of
malignancy.

\textbf{Investigations:}

ECG showed septal ST-segment elevation with reciprocal depression in the
inferior and lateral leads (Figures 1 and 2). His high-sensitivity
troponin was 115 ng/L. Chest x-ray showed bilateral atypical infiltrate
superimposed with pulmonary edema (Figure 3).

\textbf{Procedure:}

The patient underwent emergent cardiac catheterization, showing similar
findings as the last angiogram; however, due to persistent chest pain,
revascularization of the RCA with two drug-eluting stents (Figures 4 A -
E) was done. He had persistent symptoms despite revascularization. A
transthoracic echocardiogram (TTE) revealed reduced LVEF at 38\% and a
mass compressing the right ventricular apex (Figures 5 A - C). A cardiac
magnetic resonance imaging (MRI) showed a large fungating invading mass
on the superior left upper lung field near the bifurcation of the
pulmonary artery (Figures 6 A \& B).~ This mass had originated outside
the pericardium, infiltrating the surrounding structures, including the
superior aspect of the right ventricle, pulmonary artery, and
mediastinal tissue. A chest Computed Tomography (CT) demonstrated a
large invasive anterior mediastinal mass measuring 10.5 x 8.4 x 6.9 cm,
consistent with MRI.~ (Figure 7). CT-guided biopsy finally revealed
malignant SCC. A positron emission tomography scan and brain MRI
revealed metastases to the brain and adjacent lymph nodes (Figures 8 A -
D). Chemotherapy was not tolerated well due to severe axonal neuropathy.
Following an extensive discussion about the prognosis, the family and
the patient opted for hospice care.

\textbf{Discussion:}

Lung cancer is the most common malignancy worldwide, contributing to 1.8
million deaths in 2018 (2). This cancer typically metastasizes to the
liver and adrenal glands via hematogenous spread (3).~ Metastatic
cardiac masses usually affect the pericardium due to preferential
metastatic pathways involving lymphatics. Myocardial metastatic
involvement from lung cancer is infrequent (4). Histopathologic
differentiation of lung malignancy has a differential predilection to
cardiac metastases, with lung adenocarcinoma contributing to 21\% and
lung SCC contributing 18.2\% of total secondary cardiac tumors (1). The
most common presentation of patients with cardiac metastasis depends on
the type of involvement and the anatomic location. Patients can present
with dyspnea, pedal edema, chest pain, palpitation due to various
arrhythmias, and life-threatening presentations such as syncope, stroke,
cardiac tamponade, cardiac rupture, acute myocardial infarction,
pulmonary embolism, and sudden cardiac death (5). Abe et al., 1991
conducted a study on 151 lung cancer patients; 11.9\% of these patients
had myocardial involvement (6). Similarly, Cate et al., 1986 performed a
retrospective analysis on 1046 patients and reported that new onset ECG
changes highly suggest myocardial involvement in a clinically stable
patient with malignancy (7). However, it is essential to remember that
cardiac involvement is asymptomatic in most patients diagnosed with
postmortem, precluding obtaining an ECG. TTE remains the diagnostic
modality of choice, followed by conformation with additional imaging and
biopsy.

The described patient had significant risk factors for lung cancer,
including smoking and age. However, he had a normal screening CT scan
done one year ago. Chest x-rays from the current and last admission
showed nonspecific findings and failed to demonstrate lung mass. During
his first ``STEMI,'' the patient presented with chest pain and
ST-segment elevation with reciprocal changes and elevated cardiac
biomarkers, revealing stable severe CAD with patent grafts. However,
after the initial PCI, the patient's condition improved, and other
diagnostic studies did not suggest malignancy, so he was discharged. In
his second admission with ``STEMI,'' he has a similar representation,
leading to a coronary angiogram. The RCA was revascularized, assuming it
must be the culprit lesion. A subsequent TTE showed the suspicion of
cardiac mass, leading to a cardiac MRI and biopsy, revealing the
diagnosis of invasive SCC of the lung metastasizing to the myocardium.
The following pathways are identified for secondary cardiac metastasis:
a) Hematogenous, b) lymphatic, c) transvenous, and d) direct extension.
The hematogenous route leads to myocardial involvement. The lymphatic
and direct extension leads to pericardial involvement (8). The described
patient has myocardial involvement, indicating hematogenous metastasis.
However, the patient had adjacent lymph node involvement but,
surprisingly, no pericardial involvement.

The left upper lung mass remained undiagnosed despite multiple prior
imaging modalities, including screening low-dose CT scans and numerous
chest X-rays. A TTE in the presence of recurrent symptoms and persistent
ST-segment elevation led to further investigations and diagnosis. In the
described case, due to the presence of severe native CAD, it was
difficult to exclude ischemic etiology. Patients with normal coronary
arteries or mismatched ST elevation should undergo further
investigations before discharge.

\textbf{Conclusion:}

The case emphasizes the importance of differential diagnosis when
patients present with recurrent STEMI-like symptoms despite optimal
invasive treatment. The patient was finally diagnosed within three weeks
of the first presentation. Cardiac involvement is a late presentation of
metastatic lung cancer, so the outcome might not change, but unnecessary
invasive studies could have been avoided. Discussing the management of
invasive lung carcinoma with cardiac metastasis is beyond the scope of
this article.

\textbf{Learning Objective:}

Cardiac metastasis should be included in the differential diagnosis of
patients with acute coronary syndrome.

A TTE should be performed in all patients with recurrent myocardial
infarction; if the imaging window is suboptimal or suspicion remains
high, further imaging modalities should be pursued.\textbf{~}

\textbf{Funding}

None

\textbf{Author contributions}

N.J, S.T, D.C, designed and drafted the initial manuscript. Resources
and literature search done by all the authors. S.T, D.C, S.A, P.R, H.A,
G.K, K.P, A.A provided review and editing. All authors have read and
approved the final manuscript.

\textbf{Acknowledgments}

None

\textbf{Data availability statement}

Not Applicable.

\textbf{Competing interests}

The authors declare that they have no competing interests.

\textbf{Consent for publication}

Not applicable

\textbf{Ethical approval}

Not applicable

\textbf{Consent to participate.}

Was taken and is available on request.

\textbf{References:}

1. 1 Bussani R, De-Giorgio F, Abbate A, Silvestri F. Cardiac
metastases.\emph{Journal of Clinical Pathology}. 2007;60:27--34. 2.
Siegel RL, Miller KD, Jemal A. Cancer statistics, 2018. \emph{CA A
Cancer J Clinicians}. 2018;68:7--30. 3. Milovanovic I, Stjepanovic M,
Mitrovic D. Distribution patterns of the metastases of the lung
carcinoma in relation to histological type of the primary tumor: An
autopsy study. \emph{Ann Thorac Med}. 2017;12:191. 4. Reynen K,
K\selectlanguage{ngerman}öckeritz U, Strasser RH. Metastases to the heart.\emph{Annals of
Oncology}. 2004;15:375--381. 5. Yusuf SW, Bathina JD, Qureshi S, et al.
Cardiac Tumors in a Tertiary Care Cancer Hospital: Clinical Features,
Echocardiographic Findings, Treatment and Outcomes. \emph{Heart
International}. 2012;7:hi.2012.e4. 6. Abe S, Watanabe N, Ogura S, et al.
Myocardial Metastasis from Primary Lung Cancer: Myocardial
Infarction-like ECG Changes and Pathologic Findings. \emph{Jpn J Med}.
1991;30:213--218. 7. Cates CU, Virmani R, Vaughn WK, Robertson RM.
Electrocardiographic markers of cardiac metastasis. \emph{American Heart
Journal}. 1986;112:1297--1303. 8. Ete T, Jha P, Barman B, et al.
Squamous Cell Carcinoma of Lung Atypically Involving Heart: A Case
Report With Literature Review.\emph{Cardiol Res}. 2015;6:329--331. 9.
Prichard RW. Tumors of the heart; review of the subject and report of
150 cases. \emph{AMA Arch Pathol}. 1951;51:98--128.

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