We report a male patient with atypical carcinoid tumor diagnosed by anterior mediastinotomy and biopsy after a mass was observed by chance on a chest film. The presence of neuroendocrine markers, notably chromogranin, cytokeratin, synapto-physin and neuro-specific enolase, facilitated diagnosis. Because the tumor was infiltrative, full surgical excision and radiotherapy to the mediastinum (50 Gy) were provided. We describe the incidence, clinical presentation, diagnosis, treatment and prognosis of these tumors.