The author herein reports a large cell neuroendocrine
carcinoma (LCNEC) of the lung diagnosed at a brain
metastasis without clinical data. A 70-year-old man underwent
esophagectomy for
esophageal squamous cell carcinoma, and was treated with
chemotherapy. At 72 years of age, he was found to have prostatic well differentiated
adenocarcinoma, and treated by
estrogen. At 78 years of age, he was pointed out to have gastric advanced
tumor, and the biopsy showed moderately differentiated
tubular adenocarcinoma. The gastric
carcinoma was treated by
chemotherapy. At 79 years of age, he was shown to have right lung shadow (2 cm in diameter) and brain shadow (cerebellar vermis) of 1 cm in diameter. Multiple biopsy and cytology of the lung failed to detect
carcinoma cells. Biopsy of the brain was performed. The biopsy showed medullary
undifferentiated carcinoma. Immunohistochemically, the
tumor cells were positive for pancytokeratin AE1/3,
synaptophysin, CD56 (
NCAM), p53, Ki67 (labeling 40%), KIT and TTF-1, but were negative for
vimentin,
chromogranin,
neuron-specific enolase and PDGFRA. A pathological diagnosis of metastatic LCNEC form the lung was made. A molecular genetic analysis for KIT (exons 9, 11, 13, and 17) and PDGFRA (exons 12 and 18) genes identified no mutations of the KIT and PDGFRA genes. The patients died of
carcinomatosis one month after the diagnosis. In conclusion, careful histological and immunohistochemical examination can diagnose LCNEC of the lung at the metastatic site.