Paraneoplastic diarrhea in a patient with lung adenocarcinoma.

We present a case of newly diagnosed lung adenocarcinoma and a five-month history of diarrhea. The patient was found to have elevated chromogranin A serum levels and the tumor displayed histologic and immunohistochemical features of neuroendocrine differentiation. Upon lobectomy and tumor resection, the chromogranin A levels normalized and the diarrhea resolved completely. This is the first reported case of paraneoplastic diarrhea associated with lung adenocarcinoma.