Combined large cell neuroendocrine carcinoma and spindle cell carcinoma of the lung.

We report a unique case of a combined pulmonary large-cell neuroendocrine carcinoma and spindle-cell carcinoma. The patient was a 54-year-old female smoker who presented with a 4-month history of increased left-sided chest pain and exertional dyspnea. The left upper lobectomy specimen revealed an 8.0-cm mass with central necrosis. Microscopically, the epithelial areas were composed of well-defined nests of large cells with peripheral palisading expressing low-molecular-weight keratin, synaptophysin, chromogranin, and neuron-specific enolase. The spindle-cell component consisted of pleomorphic cells arranged in fibrosarcoma and malignant fibrous histiocytoma-like patterns. These spindle cells were positive for low-molecular-weight keratin and vimentin with focal expression of CD68 and muscle-specific actin. Electron microscopy in the spindle-cell areas showed cell junctions and numerous tonofilaments, indicative of epithelial differentiation. The tumor behaved aggressively and the patient died with extensive metastases 4 months after surgery. The combination of neuroendocrine malignancies and spindle-cell carcinomas appears to be uncommon in the lung. Previous reports have described this association in single case reports of anaplastic small-cell carcinoma and atypical carcinoid, but not in large-cell neuroendocrine carcinoma.