Primary mediastinal paraganglioma associated with a familial variant in the succinate dehydrogenase B subunit gene

Paraganglioma of the anterior superior mediastinum: Presentation of a case of mistaken diagnosis so long and review of the literature

INTRODUCTION AND IMPORTANCE

Mediastinal paraganglioma is a rare tumor with neuroendocrine activity, highly susceptible to misdiagnosis. Herein, we present a case misdiagnosed as Castleman disease for nearly a decade, significantly enlarged, lost the opportunity of thoracoscopic surgery, and was removed by median thoracotomy.

CASE PRESENTATION

A 59-year-old woman complained of having a mediastinal mass, was diagnosed with Castleman disease for nearly a decade and was admitted to the hospital due to neck tightness. The tumor size was significantly enlarged. We proceeded to interventional angiography with gelatin sponge angioembolization, and the tumor was resected through a median sternotomy on the second day. The operation was smooth, and the tumor was gray and slightly brittle. Postoperative pathology confirmed paraganglioma; lymph node metastasis was not detected (0/3).

CLINICAL DISCUSSION

Mediastinal paraganglioma is a rare tumor and can be either functional or nonfunctional. It can be differentiated from many diseases. The SSTR-PET-CT labeled with 68Ga-somatostatin analog, plasma metanephrine, and normetanephrine are essential for the diagnosis. Surgical resection is the most effective form of treatment. Pre-operative embolization of the feeding artery is considered to have a low rate of intraoperative bleeding. We recommend making comprehensive preparations to ensure perioperative safety and long-term survival.

CONCLUSION

When a vascularized mass is discovered in the mediastinum, surgeons should consider the possibility of a paraganglioma. Multidisciplinary consultation should be involved in the formulation of treatment plans. Lifelong surveillance for residual tumor growth and recurrence is required.

Cardiac Paraganglioma in a 14-Year-Old

Cardiac paraganglioma (PGL) is a rare catecholamine-secreting tumor forming 1% to 3% of cardiac tumors. Although most PGL occur sporadically, evidence exists that 40% of them may be related to familial cancer predisposition syndromes. We present a unique case of a 14-year-old female who presented with persistent hypertension and was found to have a cardiac PGL. During surgical resection, even though the main right coronary was preserved, the sinoatrial (SA) nodal artery was surrounded by the tumor and required resection with the tumor. The patient subsequently developed SA node dysfunction and is currently being evaluated for placement of a permanent pacemaker.

Resection of a functioning intrapericardial paraganglioma associated with succinate dehydrogenase B mutation

Functional paragangliomas are rare neuroendocrine tumours that secrete catecholamines and are infrequently found in the mediastinum. We report a case of a young male with symptoms of catecholamine excess and a personal and family history of the paraganglioma predisposing succinate dehydrogenase subunit B mutation. The lesion had anatomical intrapericardial juxtaposition to important cardiac anatomy and posed the significant challenge of dissection at surgery. The lesion was successfully resected via sternotomy on cardiopulmonary bypass and confirmed histopathologically as paraganglioma. Intrapericardial paraganglioma is rare and treatment is difficult and time critical considering the proximity of cardiac anatomy as well as malignant potential.

The Diagnosis and Clinical Significance of Paragangliomas in Unusual Locations

Paragangliomas are neuroendocrine neoplasms, derived from paraganglia of the sympathetic and parasympathetic nervous systems. They are most commonly identified in the head and neck, being most frequent in the carotid body, followed by jugulotympanic paraganglia, vagal nerve and ganglion nodosum, as well as laryngeal paraganglia. Abdominal sites include the well-known urinary bladder tumors that originate in the Organ of Zuckerkandl. However, other unusual sites of origin include peri-adrenal, para-aortic, inter-aortocaval, and paracaval retroperitoneal sites, as well as tumors in organs where they may not be expected in the differential diagnosis of neuroendocrine neoplasms, such as thyroid, parathyroid, pituitary, gut, pancreas, liver, mesentery, lung, heart and mediastinum. The distinction of these lesions from epithelial neuroendocrine neoplasms is critical for several reasons. Firstly, the determination of clinical and biochemical features is different from that used for epithelial neuroendocrine tumors. Secondly, the genetic implications are different, since paragangliomas/pheochromocytomas have the highest rate of germline susceptibility at almost 40%. Finally, the characterization of metastatic disease is unique in these highly syndromic lesions. In this review, we summarize updated concepts by outlining the spectrum of anatomic locations of paragangliomas, the importance of morphology in establishing the correct diagnosis, the clinical implications for management, and the impact of genetics on the distinction between multifocal primary tumors compared with malignant disease.