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Atypical Carcinoid Tumors of Lung: Clinicopathologic Study of Six Cases

This retrospective study of 6 cases of atypical carcinoid tumor was carried out to highlight their clinicopathological features and behavior. All patients were over 40 years of age and were treated by surgical excision of the tumor. Four tumors were central and 2 were peripherally located in the lung. Grossly, the tumors were large with spotted areas of necrosis. Microscopically, all tumors had a typical carcinoid pattern with spotted areas of necrosis and mitotic activity in the range of 2 to 5 per 10 high-power fields. On immunohistochemistry, the tumors were positive for neuron-specific enolase and cytokeratin. Follow-up ranging from 1 to 5 years was available in 4 patients; 2 are currently alive, 1 with local recurrence and distant metastasis one year postoperatively, the other with no disease after 5 years. Two patients died; one had a local recurrence at 2 years and the other had liver metastasis at 3 years.