Mediastinal paraganglioma: radiologic evaluation of an unusual vascular tumor

Diagnostic approach for mediastinal masses with radiopathological correlation

PURPOSE

Mediastinal masses have various histopathological and radiological findings. Although lymphoma is the most common type of tumor, thymic epithelial and neurogenic tumors are common in adults and children, respectively, but several other types are difficult to distinguish. No previous review has simply and clearly shown how to differentiate mediastinal masses.

METHOD

We conducted a review of the latest mediastinal classifications and mass differentiation methods, with a focus on neoplastic lesions. Both older and recent studies were searched, and imaging and histopathological findings of mediastinal masses were reviewed. Original simple-to-use differentiation flowcharts are presented.

RESULTS

Assessing localizations and internal characteristics is very important for mediastinal mass differentiation. The mass location and affected organ/tissue should be accurately assessed first, followed by more qualitative diagnosis, and optimization of the treatment strategy. In 2014, the International Thymic Malignancy Interest Group presented a new mediastinal clinical classification. In this classification, mediastinal masses are categorized into three groups according to location: prevascular (anterior)-, visceral (middle)-, and paravertebral (posterior)-compartment masses. Then, the internal characteristics and functional images are evaluated.

CONCLUSIONS

Differentiation of mediastinal masses is very difficult. However, if typical imaging findings and clinical characteristics are combined, reasonable differentiation is possible. In each patient, proper differential diagnosis may contribute to better treatment selection.

Pulmonary artery transection for resection of a middle mediastinal paraganglioma

We report the case of a 65-year-old male patient who presented with chest pain and was found to have a mediastinal paraganglioma between the left atrium and main pulmonary artery. This is the first reported case of a mediastinal paraganglioma resection utilization transection of the main pulmonary artery.

Primary pancreatic paraganglioma harboring lymph node metastasis: A case report

BACKGROUND

Primary pancreatic paragangliomas are extremely rare tumors. Limited by the diagnostic efficacy of histopathological examination, their malignant behavior is thought to be associated with local invasion or metastasis, with only four malignant cases reported in the literature to date. As pancreatic paragangliomas share similar imaging features with other types of pancreatic neuroendocrine neoplasms, they are difficult to diagnose accurately without the support of pathological evidence. As primary pancreatic paragangliomas are rare, especially those accompanied by lymph node metastasis, there is currently no consensus on treatment. Herein, we report a case of primary pancreatic paraganglioma with lymph node metastasis.

CASE SUMMARY

A mass located in the pancreatic body was incidentally discovered on computed tomography in a 41-year-old Tibetan man. Distal pancreatectomy was subsequently performed and a 4.1 cm × 4.2 cm tumor was found embedded in the body of the pancreas during surgery. Histological examination confirmed the characteristics of paraganglioma in which the neoplastic chief cells were arranged in a classic Zellballen pattern under hematoxylin-eosin staining. Further, immunohistochemistry demonstrated that the sustentacular cells in the tumor tissue were positive for S-100 protein, and neoplastic cells and pancreatic draining lymph nodes were positive for chromogranin A and synaptophysin; thus, the presence of lymph node metastasis (two of the eight resected pancreatic draining lymph nodes) was also confirmed. A diagnosis of primary pancreatic paraganglioma with lymph node metastasis was finally established. The patient remained disease-free for 1 year after the surgery.

CONCLUSION

A definite diagnosis of pancreatic paraganglioma mainly depends on postoperative histopathological and immunohistochemical examinations. Surgical resection may be the first treatment of choice for patients with primary pancreatic paraganglioma that has metastasized to the lymph nodes.

Surgical resection of a middle mediastinal paraganglioma that caused diabetes

Background

Paragangliomas are rare neuroendocrine tumors originating from chromaffin cells of extra-adrenal origin. Ninety percent of adrenergic tumors originate in the adrenal medulla and are known as pheochromocytomas; the remaining 10% are extra-adrenal and are called paragangliomas. Mediastinum paragangliomas is rare and commonly originate from the posterior mediastinum, while those originating from the middle posterior are quite rare. Some paragangliomas secrete catecholamines, leading to symptoms such as hypertension, tachycardia, and diabetes.

Case presentation

A 76-year-old woman visited our hospital for the treatment and further evaluation of diabetes. Her hemoglobin A1c levels had risen to 11.0%. To investigate the cause of her diabetes, a contrast-enhanced chest computed tomography scan was performed, revealing a ring-enhancing tumor (30 × 30 mm) in the middle mediastinum. The surgical resection was performed via video-assisted thoracic surgery. Surgery was performed using a vessel-sealing device; however, bleeding was persistent from the surrounding tissue. Total bleeding was 400 g. Blood pressure fluctuations and arrhythmia did not occur during the operation. The patient’s uncontrolled diabetes was cured after the surgery, and the tumor was diagnosed as a functional paraganglioma.

Conclusions

We encountered a rare case of functional paraganglioma located in the middle mediastinum. Functional paragangliomas should be considered as a potential cause of uncontrolled diabetes, and a whole-body CT scan should be performed to investigate this possible cause.

Paragangliomas Throughout the Body: Hereditary Syndromes and Imaging Features Including 3D Cinematic Rendering

Paragangliomas are highly vascular neuroendocrine tumors that arise from embryonic neural crest cells. They may either be hormonally active (sympathetic) or silent (parasympathetic). Approximately one-third are hereditary, and patients may develop multiple paragangliomas. Presurgical planning involves medical management as well as interventional and/or surgical techniques that must address vascular supply. Contrast-enhanced CT is the best initial anatomical study and shows the hypervascularity and feeding vessels. 3D cinematic rendering using multiplanar light sources can highlight spatial relationships of a mass to adjacent structures and help in surgical planning. This article will review the clinical presentation of paragangliomas, genetic syndromes, presurgical management, and tumor behavior and imaging appearance by location with a particular emphasis on 3D cinematic rendering.

Challenges in the surgical treatment of undiagnosed functional paragangliomas: A case report

INTRODUCTION

Paragangliomas (PGs) or extra-adrenal pheochromocytomas are rare neuroendocrine neoplasms of ubiquitous distribution. Those that produce excess catecholamine are categorized as functional, and those that do not are categorized as nonfunctional. Although modern medical technology is becoming more widespread, there are still substantial risks of misdiagnosis or missed diagnosis of PGs.

CASE PRESENTATION

A 38-year-old woman who lived in an autonomous region of inner Mongolia presented complaining of having experienced coughing for approximately the past month. Chest computed tomography (CT) and magnetic resonance imaging (MRI) revealed a lesion on the right side of thoracic vertebra 5-8 of approximately 66 mm × 54 mm, and it was deemed to be a mediastinal tumor that required surgical treatment. The patient exhibited severe hemodynamic instability during the operation, resulting in substantial challenges and risks with regard to anesthesia management.

CONCLUSION

When a patient is suspected having PG, whether the surgery should be continued or not depends on their overall condition and whether hemodynamic fluctuation can be controlled to within the normal range. Both are factors that should be considered during intraoperative management. Communication between the surgeon and anesthesiologist is necessary, in order to accurately assess the risks associated with the operation. The combination of central venous pressure and the Flotrac/Vigileo system may provide precise guidance for complementary liquid therapy and reduce cardiopulmonary complications. After the operation, hemodynamic changes should be monitored continuously in the intensive care unit, and vasoactive drugs are required to avoid postoperative hypotension. Dramatic hemodynamic changes are certainly a challenge for patients and anesthesiologists, regardless of their origin, and sufficient attention should be paid to avoid serious consequences.

Pulmonologist's Road Map to Mediastinal Lymph Node Imaging

Mediastinal lymph node station maps are intended to facilitate nodal staging in patients with non-small cell lung cancer. These maps have been revised over time and the International Association for Study of Lung Cancer (IASLC) map is the latest rendition. This article illustrates the imaging appearance of each of the IASLC map mediastinal lymph node stations, overviews some of the mediastinal lymph node sampling techniques, and discusses common pitfalls of the IASLC map. It also reviews mediastinal anatomic variants and pathologic features that may simulate lymphadenopathy.

Angiography Before Posterior Mediastinal Tumor Resection: Selection Criteria and Patient Outcomes

BACKGROUND

Resection of posterior mediastinal tumors may be complicated by bleeding or neurologic injury. Preoperative spinal angiography of mediastinal tumors has been underreported or not commonly practiced. This study evaluated the selection criteria and outcomes of patients with posterior mediastinal tumors who underwent preoperative angiography and embolization.

METHODS

This was a single-institution retrospective study of patients with posterior mediastinal tumors from 2002 to 2016. Multilevel spinal angiography was performed, with or without selective arterial embolization of vascular supply, in patients selected by thoracic or neurologic surgeons.

RESULTS

Ten of 87 patients (11%) with posterior mediastinal tumors underwent preoperative angiography. A mean of 11 arteries (range, 2 to 25) were studied. Embolization in 7 of 10 patients successfully occluded 1 to 3 arteries. There was no significant difference in age, sex, body mass index, American Society of Anesthesiologists Physical Status Classification, operative time, operative blood loss, complications, or death between patients with or without angiography. Patients who underwent angiography had larger tumors (1,490 vs 97 cm³, p < 0.0001), involvement of the neuroforamen (44% vs 10%, p < 0.05), and a longer hospital stay (9 vs 4.5 days, p < 0.05). Angiography was complicated in 1 patient by vocal cord ulceration after intubation of a tumor-compressed trachea. Shared blood supply between the tumor and the spinal cord precluded embolization and tumor resection in 1 patient. Use of angiography increased over time.

CONCLUSIONS

Selective preoperative angiography for evaluation of posterior mediastinal tumors identifies arterial variations, threatened spinal arteries, and targets for embolization. The specific role of angiography and embolization requires further investigation to standardize indications and protocols for the number of arteries examined.

Imaging of Intrathoracic Paragangliomas

Intrathoracic paragangliomas are uncommon and only represent 1%-2% of paragangliomas. They are most commonly found in mediastinal compartments (aortopulmonary window or posterior mediastinum). Computed tomography, magnetic resonance, and specific nuclear medicine radiotracers are routinely used to characterize these lesions and help exclude other more common conditions. Selective angiography is currently used for preoperative embolization and mapping of the vascular supply before surgical resection, rather than for diagnostic purposes alone.

Incidental posterior mediastinal paraganglioma: The safe approach to management, case report

INTRODUCTION

Paragangliomas are neuroendocrine tumors arising from chromaffin cells located in sympathetic paraganglia. Mediastinal paragangliomas are extremely rare and can be classified as functional or non-functional according to their ability for secreting catecholamines. Patients can be asymptomatic and the diagnosis is usually incidental. Complete surgical resection remains the standard of care for paragangliomas.

PRESENTATION OF CASE

We present a 44-year-old woman with a functional mediastinal paraganglioma incidentally found during the perioperative imaging workup for a diagnosed breast carcinoma. Chest radiograph and computed tomography (CT) showed a well-defined lesion in the posterior mediastinum suspicious for an esophageal malignancy. Endoscopic and CT-guided biopsies were performed confirming the diagnosis of a neuroendocrine tumor. Laboratory studies showed elevated catecholamines and chromogranin A levels, consistent with a paraganglioma. Appropriate pre-operative management was done and successful surgical resection without catecholamine related complications was achieved.

DISCUSSION

The workup and treatment of incidentally discovered adrenal and extra-adrenal lesions are controversial. Because of the absence of symptoms and the wider differential diagnosis of extra-adrenal lesions, an attempt for biopsying and surgically remove these lesions prior to biochemical testing is not an uncommon scenario, although this could be potentially harmful. Surgeons should have an index of suspicion for catecholamine-secreting tumors and hormonal levels should be assessed prior to biopsy or surgical resection.

CONCLUSION

Surgeons should consider paragangliomas as a differential diagnosis for extra-adrenal lesions. Biochemical testing with catecholamines and chromogranin A levels should be performed prior to biopsy or surgical removal in order to avoid catastrophic complications.

Mediastinal paragangliomas: association with mutations in the succinate dehydrogenase genes and aggressive behavior

Extra-adrenal pheochromocytomas, otherwise known as paragangliomas (PGLs), account for about 20% of catecholamine-producing tumors. Catecholamine excess and mutations in the genes encoding succinate dehydrogenase subunits (SDHx) are frequently found in patients with PGLs. Only 2% of PGLs are found in the mediastinum, and little is known about genetic alterations in patients with mediastinal PGLs, catecholamine production by these tumors, or their clinical behavior. We hypothesized that most mediastinal PGLs are associated with germ line SDHx mutations, norepinephrine and/or dopamine excess, and aggressive behavior. The objective of this study was to characterize genetic, biochemical, and clinical data in a series of ten patients with mediastinal PGLs. All ten primary mediastinal PGL patients had germ line SDHx mutations, six in SDHB, and four in SDHD genes. Chest or back pain were the most common presenting symptoms (five patients), and catecholamines and/or their metabolites were elevated in seven patients. Additional tumors included head and neck PGLs in four patients, pheochromocytoma in one patient, and bladder PGL in another. Metastatic disease was documented in six patients (60%), and a concurrent abdominal mass was found in one patient. We conclude that mediastinal PGLs are strongly associated with SDHB and SDHD gene mutations, noradrenergic phenotype, and aggressive behavior. The present data suggest that all patients with mediastinal PGLs should be screened for SDHx gene mutations, regardless of age.

A rare cause of hypertension in children: intrathoracic pheochromocytoma

Mediastinal pheochromocytomas account for only a small fraction of mediastinal tumors. Most commonly, these tumors are located in posterior mediastinum. Increasing number of cases of pheochromocytomas is being reported from middle mediastinum. Excision of mediastinal paraganglioma is often hazardous because of its rich blood supply and tendency to involve surrounding structures. It can be a big challenge to manage asymptomatic cases of pheochromocytoma intraoperatively. It is imperative that these patients receive adequate alpha adrenergic and if necessary beta adrenergic blockade. Adequate preoperative preparation with alpha and beta blockers may not prevent serious intraoperative hypertension. We report a case of posterior mediastinal pheochromocytoma which was biochemically active preoperatively. We review the presentation, diagnosis and management of intrathoracic pheochromocytomas including cardiac pheochromocytomas.

Preoperative embolization followed by surgical excision of an intrapericardial pheochromocytoma

A teenager with palpitations and hypertension was found to have an intrapericardial pheochromocytoma of the left atrium with multiple feeding collaterals. Radiologic embolization was carried out on the major feeding arteries to the tumor preoperatively with good angiographic result. Surgery was carried out the following day through a median sternotomy approach and cardiopulmonary bypass. Minimal bleeding was observed due to prior embolization. The patient made a rapid postoperative recovery and was discharged 7 days later.

Extraadrenal paragangliomas of the body: imaging features

OBJECTIVE

This article illustrates the anatomic distribution of the healthy paraganglion system and the imaging and pathologic features of various extraadrenal paragangliomas occurring in the head and neck, chest, and abdomen.

CONCLUSION

Although paragangliomas can occur in a variety of anatomic locations, the majority are seen in relatively predictable regions of the body. Extraadrenal paragangliomas have nearly identical imaging features, including a homogeneous or heterogeneous hyperenhancing soft-tissue mass at CT, multiple areas of signal void interspersed with hyperintense foci (salt-and-pepper appearance) within tumor mass at MRI, and an intense tumor blush with enlarged feeding arteries at angiography.

Nonfunctioning malignant paraganglioma of the posterior mediastinum with spinal cord compression. A case report

STUDY DESIGN

Case report and review of the literature.

OBJECTIVE

To present a case with an uncommon nonfunctioning malignant paraganglioma of the posterior mediastinum with compression of the spinal cord. An update survey is given with respect to diagnostic, histopathologic, and therapeutic aspects of paragangliomas.

SUMMARY OF BACKGROUND DATA

Paragangliomas in the posterior mediastinum are uncommon and rarely may produce spinal cord compression. To illustrate the low incidence, only two cases of paraganglioma of the posterior mediastinum were reported by the Mayo Clinic, Rochester, Minnesota, during a 40-year period.

METHOD

Case report and review of the literature.

RESULT

The diagnosis was made by modern imaging techniques (computed tomography, magnetic resonance imaging, and metaiodobenzylguanidine scan) and verified by computed tomography guided per thoracic puncture. A wide local resection was performed; the patient is disease-free 1 year after surgery.

CONCLUSION

The uncertainty of prognosis and possibility of local recurrence of paragangliomas even after a long period emphasizes the importance of wide local surgical resection with or without adjuvant therapy and makes long-term follow-up and continued surveillance of the patient mandatory.

Paraganglioma of the posterior mediastinum: value of magnetic resonance imaging

A case of paraganglioma arising in the posterior mediastinum in a 29-year-old man diagnosed by magnetic resonance imaging is reported. Excision of mediastinal paraganglioma is often hazardous because of its rich vascular supply and tendency to involve surrounding structures. Magnetic resonance imaging is valuable for the preoperative diagnosis of this vascular tumor as well as for determination of its resectability and appropriate surgical procedure.