CEA-producing mucin-negative gastric signet-ring cell carcinoma with neuroendocrine markers - A case report

Biopsy and autopsy materials excised from a 69-year-old woman were investig ated. Serum carcinoembryonic antigen (CEA) showed a high value of 955 ng/mL . A plateaulike tumor was located in the gastric cardia and fundus to the e ntire gastric body. It showed severe proliferation and infiltration from th e mucosa to the serosa. The tumor was comprised of signet-ring cells and po orly differentiated adenocarcinoma cells, which spread into the submucosa o f the pylorus, duodenum, and jejunum. Signet-ring cells had a large, eccent ric vesicular nucleus and a pale cytoplasmic inclusion. Poorly differentiat ed adenocarcinoma cells had a pleomorphic nucleus, small eosinophilic nucle olus, and abundant eosinophilic cytoplasm. Both neoplastic cells were posit ive for CEA. epithelial membrane antigen, Leu-7 (CD57), and neuron-specific enolase, and were negative for cytokeratin, vimentin, and periodic acid-Sc hiff, Alcian blue, and mucicarmine stains. Electron microscopy showed endoc rine granules with a limiting membrane measuring approximately 238 nm in di ameter in the cytoplasm. The authors diagnosed this patient as having mucin -negative gastric signet-ring cell carcinoma with neuroendocrine markers, w hich is suggested to exist among poorly differentiated adenocarcinoma, undi fferentiated carcinoma, and signet-ring cell carcinoma.