An extremely large solitary primary paraganglioma of the lung: report of a case

Frequency and extent of cytokeratin expression in paraganglioma: an immunohistochemical study of 60 cases from 5 anatomic sites and review of the literature

The absence of cytokeratin expression in paraganglioma helps to differentiate it from other neuroendocrine neoplasms such as carcinoid tumor. Although rare cytokeratin positive paragangliomas have been reported, there are no large systematic studies of this phenomenon. The aim of this study was to determine the frequency and extent of cytokeratin expression in paragangliomas using a large cohort of cases from multiple anatomic sites. Immunohistochemical staining for keratin AE1/AE3 (mouse monoclonal, MAB3412; Millipore) and CAM 5.2 (mouse monoclonal, 349 205; Becton-Dickinson) was performed on whole-tissue sections from 60 resected paragangliomas from the head and neck (36), thorax (10), abdomen (8), intradural/epidural spine (5) and bone, left iliac (1). Cytokeratin expression was identified in only 2/60 (3.3%) cases. One was a mediastinal paraganglioma with moderate to strong expression of keratin AE1/AE3 and CAM 5.2 in <5% tumor cells. The other was a lumbar intradural paraganglioma positive for CAM 5.2 (moderate to strong, 80% of tumor cells) but negative for keratin AE1/AE3. All other paragangliomas (58/60, 96.7%) were negative for keratin AE1/AE3 and CAM 5.2. This study - the largest series of cytokeratin-stained whole-tissue sections of paragangliomas to date - supports the dictum that most paragangliomas are cytokeratin negative. Rare exceptions may be site-related.

Pulmonary and mediastinal paragangliomas: rare endothoracic malignancies with challenging diagnosis and treatment

Background

Pulmonary and mediastinal paragangliomas are rare tumors that may have neuroendocrine activity or be non-functional, incidental, in asymptomatic patients, or causing mass effect symptoms. Although being low-grade tumors, they can display an aggressive behaviour, developing local infiltration and distant metastases. We report our experience with three endothoracic paragangliomas and a Literature review, to point out diagnostic difficulties and problems related to surgical treatment.

Methods

From 2009 to 2017, we treated 3 patients with histological diagnosis of paraganglioma: 2 pulmonary, 1 mediastinal. No one presented catecholamine-secreting syndromes; pulmonary cases were asymptomatic, while the mediastinal one had aspecific cough and dyspnea. Imaging diagnosis was based on chest computerized tomography (CT) and magnetic resonance imaging (MRI) scan. No patient had preoperative histological diagnosis. Intraoperative pathological examination was suggestive for malignancy: in pulmonary cases, wedge resection and lobectomy were performed; the middle mediastinal mass was completely removed after challenging dissection, isolation and section of numerous vascular pedicles.

Results

Postoperative course was uneventful in all cases. No patient received adjuvant treatments. At a median follow-up of 47 months (range, 6-102 months), two patients are alive, without local or distant recurrence; one patient died 6 months after surgery, due to disease progression.

Conclusions

Endothoracic paragangliomas, rare and often asymptomatic tumors, are of difficult diagnosis and should be considered malignant tumors, due to the potential aggressive behaviour of cases with high mitotic index and the frequent possibility of recurrence and metastases. Surgical resection is the treatment of choice and careful intraoperative manipulation is recommended, due to the high vascularity of these tumors, to prevent complications. After complete excision, long-term prognosis is generally good. However, even after surgical removal, a close, periodical and life-long follow-up is mandatory.

Primary paraganglioma of the lung: a case report and literature review

Only 22 cases of primary pulmonary paraganglioma have been reported previously. This report presents a case of paraganglioma that arose in the lung of a 38-year-old woman who presented with chest pain and paroxysmal cough with little sputum. Positron emission tomography-computed tomography scan demonstrated two homogeneous masses in the left lower lobe accompanied by multiple mediastinal lymph node metastases. After resection, gross pathological examination confirmed two solid masses, which had a yellow-grey complexion and decreased blood supply and that invaded the mediastinum. Immunohistochemical analysis confirmed the presence of several biological tumour markers. This is the first known report to describe the computed tomography imaging characteristics of a paraganglioma, thereby improving understanding of its morphological features and helping in the differential diagnosis of lung tumours.

Pulmonary paraganglioma manifesting as an endobronchial mass

Thoracic paragangliomas comprise only 1-2% of all paragangliomas, including the adrenal pheochromocytomas, and these tumors are mostly found in the mediastinal compartments (1). To the best of our knowledge, there is only one case report in the pathology literature of endobronchial involvement by a primary pulmonary paraganglioma (2). We report here on the CT and bronchoscopic findings of a case of pathologically proven endobronchial paraganglioma in a 37-year-old woman. In our case, bronchoscopy and CT demonstrated an endobronchial hypervascular mass, which indicated the presence of carcinoid or hypervascular metastasis based on the known incidence of such tumors.

Primary paraganglioma of the lung

There are few reported cases of primary pulmonary paraganglioma in the pathology literature. Given the historical confusion surrounding bronchial tumors, widespread use of the term "chemodectoma" and classification of these lesions as paraganglioma in an outdated World Health Organization classification of lung tumors, the recognition of tumors arising from paraganglia within the lung has not been accepted by leading authorities. We present a well-documented case of a primary pulmonary paraganglioma with typical morphologic features and a supporting immunohistochemical profile. The 0.9 cm endobronchial tumor was submucosal and composed of nests of ovoid cells with abundant eosinophilic cytoplasm, cytoplasmic vacuoles, round to oval nuclei with speckled chromatin, and occasional conspicuous nucleoli. The nests of cells were surrounded by thin-walled vascular channels and stellate spindle cells. The ovoid cells showed strong diffuse staining for chromogranin A, synaptophysin, and faint staining for S-100; they were negative for cytokeratin AE1/AE3, Cam 5.2, and epithelial membrane antigen. The stellate spindle cells stained intensely positive for S-100 protein. A critical review of reported cases of pulmonary chemodectomas and paragangliomas in the English literature features few, if any, well-documented examples. While this exceedingly rare tumor should be discerned from carcinoid tumor, it remains unknown if primary pulmonary paragangliomas behave aggressively like intra-abdominal extra-adrenal paragangliomas, or in a more indolent manner observed with extra-adrenal paragangliomas in other locations.

Ectopic neural and neuroendocrine neoplasms

Although neural and neuroendocrine tissues are distributed virtually ubiquitously throughout the body, the occurrence of selected neoplasms related to those lineages is extremely uncommon in some topographic sites. This review considers the clinicopathologic characteristics of heterotopic pituitary adenomas; neuroendocrine carcinomas in non-organ-based locations; ectopic (extraneuraxial) meningiomas and gliomas; visceral neuroblastic neoplasms and primitive neuroectodermal tumors; and paragangliomas arising outside the sympathoadrenal neural network. Practical approaches to differential diagnosis are emphasized.

Primary Pulmonary Paraganglioma: Report of a Functioning Case With Immunohistochemical and Ultrastructural Study

We describe a case of primary pulmonary paraganglioma, a tumor that has not been reported in sufficient detail in previous literature. The patient was a 55-year-old woman with hypertension accompanied by an elevated serum norepinephrine level (2651 pg/mL; normal 100-450 pg/mL). Computed tomography revealed a well-circumscribed solid mass, 3.5 cm in diameter, located in the lower lobe of the left lung. In the lobectomy specimen, the tumor had invaded the B8 bronchus and hilar lymph nodes with microscopic metastasis to the mediastinal nodes. The tumor showed histologic, immunohistochemical, and ultrastructural features of paraganglioma: argyrophilic cells arranged in a nesting (Zellballen) or anastomosing trabecular pattern within an arcuate vascular network. Neoplastic chief cells positive for neuroendocrine markers (CD56, synaptophysin, chromogranin A) were surrounded by sustentacular cells positive for S-100 protein. Neurofilament protein was positively stained, but cytokeratins were totally negative. On electron microscopy, chief cells possessed abundant dense core granules with an eccentric halo ("norepinephrine-type" granules). The patient's blood pressure began to decline soon after the resection, and her serum norepinephrine promptly returned to almost normal. On the basis of our experience, our case is a bona fide primary pulmonary paraganglioma, a tumor heretofore subject to considerable skepticism.

Resection of a branchiomeric paraganglioma at a rare extrapulmonary location

Thoracic paragangliomas are a rare cause of hypertension. We report the occurrence of a sporadic benign norepinephrine-producing branchiomeric paraganglioma in a 32-year-old man with paroxysms of hypertension. After localization by iodine 123-metaiodobenzyl-guanidine scintigraphy and magnetic resonance imaging, the paraganglioma was resected successfully below the right pulmonary artery through a right-sided posterolateral thoracotomy. The particular location was consistent with a branchiomeric paraganglioma in an extremely rare extrapulmonary location.