A Retroperitoneal Paraganglioma Presenting as Acute Coronary Syndrome: A Rare Case Report and Literature Review

Abstract

Paragangliomas are catecholamine-secreting tumors arising from the sympathetic and parasympathetic ganglia. Here, we describe a case in which a young man who had visited the emergency room complaining of headache and shortness of breath was later found to have acute coronary syndrome with accompanying cardio-pulmonary complications necessitating immediate cardiac intervention. Later on, during further management, he was diagnosed with a retroperitoneal paraganglioma. Thus, we try to emphasize the need for a high clinical index of suspicion and urgent radio-imaging for diagnosing this relatively rare clinical entity to prevent fatal outcomes or any long-term morbidity.

INTRODUCTION

Rare neuroendocrine tumors called paragangliomas (PGL), also known as extra-adrenal pheochromocytomas, arise from the sympathetic and parasympathetic ganglia, which are composed of scattered chromaffin cells. Chromaffin-cell tumors called pheochromocytomas originate 80%–85% from the adrenal medulla and 15%–20% from chromaffin tissues outside the adrenal glands (PGL). Parasympathetic PGL often presents with symptoms of cranial nerve palsies and accompanying mass effect, whereas sympathetic variants are linked with clinical signs relating to catecholamine excess such as headache, tachycardia, palpitation, and hypertensive crisis.[1] In their rarest presentation, a sympathetic PGL may present with acute coronary syndrome with hypertensive urgency/emergency, cardiomyopathies, arrhythmias, or acute aortic dissection.[2] We herein are presenting a case of retroperitoneal PGL with high levels of nonepinephrine which on admission presented with acute coronary syndrome.

CASE PRESENTATION

A 34-year-old male with no comorbidity reported sudden onset headache, breathlessness, and diaphoresis for 2 h. His heart rate was 74 beats per min, respiratory rate was 16–18 breaths per min, and pulse oximetry read 98% at room air. His blood pressure (BP) was 210/125 mmHg. The anterior leads of an electrocardiogram displayed hyperacute “T” waves and subtle “ST-segment elevation” [Figure 1]. A routine hemogram and cardiac enzymes were within normal limits. His two-dimensional echocardiography (2D-ECHO) showed normal ejection fraction but hypokinesia in the left anterior descending (LAD) artery territory. He underwent coronary angiography (CAG) on the same day of admission and was diagnosed to have about 80%–90% thrombotic occlusion of the LAD artery, for which he underwent coronary stenting in the same setting [Figure 2a and b]. Post CAG, the patient developed two episodes of paroxysmal hypertension along with sweating, intermittent shortness of breath, and headache. The BP fluctuated from 218/110 mmHg to 80/40 mmHg which improved to 90/50 mmHg after 200 ml of rapid intravenous fluid infusion. His BP was best controlled with a combination of oral metoprolol 5 mg once a day and gradual alpha blockage with Prazocin 5 mg tablets twice daily. A repeat urgent 2-D ECHO showed a left ventricular ejection fraction of 45%–50% and ruled out any pericardial effusion. Renal arterial color Doppler ultrasonography revealed normal Doppler indices at the origin of main renal arteries and in segmental intra-renal branches with normal color flow and without any parvus tardus spectral pattern. However, the Grayscale ultrasound localized a well-defined moderately hypoechoic mass lesion in the left anterior pararenal space which showed no significant color flow [Figure 3].

Figure 1.

Image of a 12-lead electrocardiogram with hyperacute “T” waves and subtle “ST-segment elevation”

Figure 2.

Left hand image showing 80%–90% thrombotic occlusion (red arrow) of the left anterior descending artery taken during coronary angiography (a) and right hand image showing stent (red arrow) in situ (b)

Figure 3.

Color Doppler ultrasound showing a well-defined heterogeneously hypoechoic solid mass (horizontal arrow) showing no significant intralesional color flow. The superior mesenteric artery is draping along the right border of mass

A contrast-enhanced computed tomography (CECT) image of the chest and abdomen on the 5^th day of admission showed a large well-defined smoothly marginated hypodense cystic/necrotic mass measuring about 6 cm × 6 cm × 5 cm (ap × tr × cc) in left anterior pararenal space in para-aortic location which showed subtle inhomogeneous postcontrast enhancement [Figure 4]. The adrenal glands were normal and localized separately from the mass lesion. A contrast-enhanced magnetic resonance imaging (CEMRI) of the abdomen on the 6^th day of admission also confirmed the findings and revealed the nature of the mass to be cystic/necrotic [Figure 5]. The 24-h urine metanephrine level was 469.28 µg/24 h according to a laboratory report, whereas the normetanephrine level was well above 10,300 µg/24 h. A preoperative ⁶⁸Ga-1, 4, 7, 19-tetraacetic acid (DOTA-NOC) positron emission tomography CT (PET/CT) for the primary site showed a large nonsomatostatin receptor (SSTR) expressing cystic lesion in the left suprarenal space. Adrenal glands were visualized with physiological SSTR expression. No other significant SSTR-expressing lesions were seen elsewhere. With these investigation results in hand, surgical excision was deferred for 6 months in view of ongoing treatment with antiplatelet agent drugs and a recent history of percutaneous transluminal coronary angioplasty. The patient underwent intensity-modulated radiotherapy and has been kept on a close follow-up with PET/CT and CEMRI abdomen for residual disease activity. At present, the patient is asymptomatic and comfortable with his BP and other vital parameters within normal limits.

Figure 4.

Contrast-enhanced computed tomography of the abdomen shows a well-defined homogeneously enhancing predominantly cystic mass in left anterior pararenal spaces showing no significant enhancement in arterial (white arrow, a) and Porto-venous phase (white arrow b). The left adrenal gland appears normal and localised separately from the mass (yellow arrow, b)

Figure 5.

Contrast-enhanced magnetic resonance imaging of the abdomen: Plain Turbo Spin Echo T2WI shows a heterogeneously hyperintense mass (red arrow) (a) which shows minimal inhomogeneous enhancement in postcontrast T1WI (red arrow) (b)

DISCUSSION

PGLs in the retroperitoneum are rare and commonly seen in the 3^rd and 4^th decades of life without a clear sex predilection.[3] They are considered nonfunctional as only a minority of them secrete catecholamines. Retroperitoneum is a rare site that makes up to 1%–3% of retroperitoneal neoplasms and about 50% of them are considered malignant and the metastatic lesions may present years after initial presentation. The cardiovascular manifestations include myocardial ischemia and infarction due to hemodynamic collapse owing to increased myocardial oxygen consumption after a mismatch between oxygen demand and supply with an increased afterload following an excessive adrenergic stimulation.[4] It may cause cardiac arrhythmias due to the stimulation of beta-adrenergic receptors. Other known cardiac manifestations are paroxysmal hypertension, hypertensive emergencies, orthostatic hypertension, shock, and cardiomyopathies. The laboratory diagnosis of this condition is obtained by 24-h urine specimen analysis for raised levels of catecholamine metabolites and metanephrines. A multiphasic CECT of the chest and abdomen has been reported to have a 93%–100% sensitivity for adrenal pheochromocytomas and 100% for extra-adrenal PGLs.[5] Magnetic resonance imaging (MRI) of the abdomen may be used for substantiating the CECT findings and ascertaining intralesional changes. The small tumors are usually homogeneous in appearance on MRI; however, large tumors show heterogeneous signals in T1W and T2W sequences.[6] Nuclear imaging with ¹²³I-meta-iodobenzylguanidine (MIBG) and ¹³¹I-MIBG scintigraphy can also be considered for tumor detection owing to the structural similarity of MIBG with norepinephrine, thus enabling its transportation to the cells through norepinephrine receptors.[7] It is further considered useful in detecting metastatic disease and is useful for follow-up patients. A ⁶⁸Ga-DOTA-NOC PET/CT is useful in localizing primary disease and metastatic lesions.[8] Complete surgical resection is the treatment of choice. Alternatively, in cases where the tumor is inoperable or surgery is contraindicated, definitive radiotherapy is employed to achieve local disease control. It is recommended to use a radiation dose of 4000–4500 cGy range to be delivered over 4–5 weeks. Chemotherapy is reserved for metastatic disease.[9]

CONCLUSION

PGLs are uncommon neuroendocrine tumors that, in extremely rare circumstances, may first appear with cardiovascular symptoms. It is prudent to have a strong clinical suspicion of pheochromocytoma or an extra-adrenal PGL in such cases. An urgent lab evaluation for epinephrine and metanephrine along with radiological imaging is strongly recommended for the localization and management of the lesion.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the legal guardian has given his consent for images and other clinical information to be reported in the journal. The guardian understands that names and initials will not be published and due efforts will be made to conceal patient identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.