Primary Pulmonary Paraganglioma, Case Report and Review of the Literature

Abstract Background: Primary pulmonary paragangliomas are extremely rare neuroendocrine tumor, counting less than 1% of all paragangliomas. The incidence of paragangliomas range between 2– 8 per million in a year. The most common site of origin is the superior paraaortic region between the diaphragm and the lower renal poles (approximately 46% of all cases), and particularly in and around the renal hilus. Most pulmonary paragangliomas are nonfunctional and result in no evident clinical symptoms. Some patients develop respiratory symptoms, such as a cough, chest pain, or dyspnea, as in our case. Case presentation: A 71-year-old woman came to our attention for cough. Active smoker of 56 p/y, her medical history consisted of a myocardial infarction, anxious-depressive syndrome, hypertension, diabetes, obesity (BMI 37.3) and Hashimoto thyroiditis. The chest radiography revealed a rounded opacity of the middle lobe. Then, a computerized tomography (CT) showing the presence of a 2.6 cm solid lesion, oval in shape, with regular margins, located in the medial segment of the middle lobe. On gross examination, a well-demarcated neoplasm, with white-brown cut surface and solid consistency was found. The tumor cells appear to be arranged in a typical nest pattern supported by a thin vascular framework producing the classic ‘zellballen’ or basket pattern. Immunohistochemical staining showing positivity for CgA, Syn and S100 (immunostaining revealed of the presence of the classic “substentacular” cells). Conclusion: Primary pulmonary paragangliomas are rare entities and their differential diagnosis with carcinoid tumors, more typical for this site, is not always easy and lies in subtle morphological and immunophenotypic differences. A correct diagnosis is important since, in 50% of the patients, mutations in tumor susceptibility genes have been reported, thus a genetic testing and counseling should be considered.