[Combined neoplasia of the lung: description of a case of adenocarcinoma mixed with typical carcinoid]

To report about a lung tumor that was a combination of typical carcinoid and adenocarcinoma.The patient, a 71-year-old male, presented with a 2.5-cm pulmonary nodule that, microscopically, was a combination of an adenocarcinoma (tubular with clear cell features and bronchioloalveolar) and a typical carcinoid. Immunohistochemically, both components were positive for cytokeratin, but only the carcinoid component was positive for chromogranin and synaptophysin. In the range of neuroendocrine tumors of the lung, a combination with other histological types of carcinoma (squamous, adeno, large cell and pleomorphic) can be found with both small cell carcinoma and large cell neuroendocrine carcinoma, but is very rare with typical and atypical carcinoids.