[Primary lung paraganglioma. A case report].

Primary lung paragangliomas are rare. They are 1-2% of the paragangliomas, and most of them occur in patients of 43-61 years. They clinically appear as solitary tumors and are in general asymptomatic. These tumors show a nesting pattern (Zellballen) of chief polygonal cells locked by fibrovascular trabeculae with subtenticular cells. The main cells have uniform nuclei with granular eosinophilic cytoplasm, and they are positive for neuroendocrinal markers (Neuron Specific Enolase, sinaptofisine and cromogranine A). Sustentacular cells are positive for protein S-100 and neurofibrilar protein. A differential diagnosis with the carcinoid tumor can be very difficult. The surgical treatment is mandatory , specially high blood pressure and the chances of malignization.