In this case report, we describe an unexpected PGL found during surgery when the patient experienced hemodynamic surges. Severe hemodynamic surges during surgery and the postoperative pathological diagnosis showed that the patient had a rare case of posterior mediastinal functional PGL. This was not detected before the operation, resulting in the patient experiencing a dangerous surgical process.
Clinically, PPGL (PCC and PGL) are incidental adrenal tumors. About 5% of adrenal incidentalomas are PPGLs [3,4,5]. Due to its secretion of catecholamines, PPGL often presents clinical symptoms such as paroxysmal or persistent hypertension, palpitations, headache, sweating, and hyperglycemia [2, 3]. Between 0.2 and 0.6% of hypertension in patients is caused by PPGL . However, some PPGLs are clinically silent, which makes the diagnosis more difficult [2, 6, 7]. PGL is a neuroendocrine tumor derived from the paraganglia of the sympathetic and parasympathetic nervous systems. They are most commonly found in the head, neck, chest, abdomen, and pelvis, while PGL located in the mediastinum are rare. PGL in rare anatomical locations may cause confusion and diagnostic errors . The patient described here had hypertension, which was well-controlled, without headache, sweating, cold extremities, or other symptoms. For this patient, the lack of symptoms and rare PGL location resulted in missing the diagnosis of PGL. Therefore, the patient did not receive sufficient preoperative preparation, which caused the hemodynamic surges during the surgery.
The primary method for the qualitative diagnosis of PPGL is the detection of hormones and their metabolites [3, 7, 9]. Determination of catecholamine metabolites can improve the sensitivity of the PPGL diagnosis. In addition, PGL/PCC have the highest rate of germline susceptibility, which is at almost 40% [10,11,12]. Thus genetic testing, combined with clinical manifestations, biochemical, and imaging assessments, can help to understand tumor secretion, tumor malignancy, and develop treatment and follow-up plans for PPGL [12, 13]. For this missed diagnosis, tests for hormones and their metabolites or genetics were not performed.
A previously reported on a patient with bilateral asymptomatic adrenal masses, which were diagnosed as nonfunctional tumors based on the negative laboratory tests (hormones and their metabolites) . Without sufficient preoperative preparation, a hypertensive crisis occurred during the right adrenal resection. Her pathology revealed a pheochromocytoma. Our patient was similar to this case, a silent PGL with severe hemodynamic fluctuations during the operation. Preoperative preparation such as α-adrenergic blockade should be considered in all PGL patients, even if the patient is clinically silent.
PPGL patients’ anesthesia management is very challenging. First, preoperative preparation should be adequate, such as the use of αblockers and augmentation of blood volume [15, 16]. Second, hemodynamic monitoring during the surgery is essential. Monitoring ABP, CVP, the cardiac output (CO), systemic vascular resistance (SVR), and stroke volume variation (SVV) (with the Flotrac/Vigileo system) can provide precise guidance to fluid management. With the guidance of hemodynamic monitoring, adequate fluid therapy and appropriate vasoactive medications can reduce cardiopulmonary complications . Third, appropriate and reasonable use of vasoactive drugs to control perioperative blood pressure fluctuations. Hypertension induced by catecholamine secretion can be treated with the following drugs such as sodium nitroprusside, urapidil, nicardipine, phentolamine, esmolol. Administration of volume expanders and antihypotensive drugs noradrenaline, phenylephrine, vasopressin, or dopamine would be critical in treating hypotension after tumor removal . Fourth, attention should be focused on the clinical manifestations and complications associated with a sudden increase or decrease in catecholamine levels after operation . When encountered intraoperatively with undetected catecholamine secreting PPGL, we should immediately perform adequate hemodynamic monitoring, prepare appropriate vasoactive agents, and give an appropriate amount of fluid treatment.
Fortunately, the patient’s hemodynamic fluctuations were treated promptly, and there were no other life-threatening severe complications. Moreover, what we can learn from this case: (1) The clinical manifestations of PGL patients are diverse, of which 50–80% are often asymptomatic [20, 21]. Patients with a potential mediastinal tumor should be identified from PGL, especially tumors near the vertebral column. Early recognition is essential to manage PGL patients properly. (2) Less hemodynamic monitoring of this patient. We only monitored ABP at that time, and CVP could not be performed as the patient was in a lateral position, and the Flotrac/Vigileo system was not available. As considering the cardiopulmonary complications of over fluid therapies, the fluid dilatation might be insufficient for less hemodynamic monitoring during the operation. This may lead to serious hypotension after the removal of the tumor. (3) Short-acting vasoactive drugs are preferred and recommended to control hypertension, such as sodium nitroprusside, urapidil, and phentolamine. In our first attempt, urapidil was ineffective for reducing hypertension. Sodium nitroprusside and phentolamine were not given priority, because we did not prepare them in advance. Nicardipine, which successfully reduced the blood pressure during the removal of the tumor, can reduce brain and kidney damage, but may lead to serious hypotension after tumor removal as it has a long duration of action. Better drug choices might be more conducive to the patient’s blood pressure management. (4) When facing an unexpected PGL with hemodynamic surges, promptly terminating the operation should be considered. If the hemodynamic surges appear at the entrance of the operation room, anesthesia induction time, changing of position, or during the operation but cannot be controlled, it should be communicated to the surgeons to cancel the surgery. In this case, hemodynamic parameters were stable until the separation of the tumor and could be controlled with vasoactive drugs and, therefore, the surgery continued.
Studies have shown that PGL have the potential to become malignant and are not sensitive to chemotherapy and radiation [3, 22]. Therefore, patients with PGL should be followed up for life after surgical treatment . We followed up this patient for over one year after the operation and found no tumor recurrence or metastasis, and will continue to follow up. The patient’s hypertension has remained stable using the same dose of nifedipine. His hypertension did not recover after the PGL tumor excision, which might confirm that the tumor was a silent PGL.