A rare case of poorly differentiated endocrine cell carcinoma of the stomach with signet ring cell differentiation

Abstract

eration [4][5][6]. PDECCs of the stomach are classifi ed as either a pure-type tumor (42%) or a composite-type tumor (58%) containing an admixture of adenocarcinoma and/or differentiated squamous type cells [7]. In almost all PDECCs the adenomatous components of composite-type tumors are well-differentiated adenocarcinomas; however, rare cases of PDECCs have poorly differentiated adenocarcinomas, including signet ring cell carcinomas [7][8][9].Tumors that exhibit dual differentiation; for example, showing both mucus production and dense core granules within the cytoplasm of the same cell, are extremely rare even among composite-type tumors [10]. A very few cases of such tumors involving the stomach have been reported previously, although the peculiar biological behavior has not been described in detail [7,11].Here, we describe a rare case of a tumor, with lymph node metastasis, showing dual differentiation composed of PDECC of the stomach containing differentiated signet ring cells, which had a poor prognosis with aggressive tumor progression. Case reportA 70-year-old woman was referred to hospital with a positive fecal occult blood test. Endoscopic examination revealed an ulcerated lesion located in the middle third of the stomach, which was diagnosed as a histologically benign ulcer. The patient was followed on an outpatient basis and on the third endoscopic examination, a gastric adenocarcinoma was confi rmed by biopsy. Computed tomography (CT) and ultrasonography showed a lymph node measuring 10 mm in diameter on the lesser curve of the stomach that was suggestive of metastasis, but no metastases at distant sites including the liver were identifi ed. Laboratory tumor markers were slightly elevated, with a carcinoembryonic antigen (CEA) level of 8.0 ng/ ml (normal range [NR] < 5.0 ng/ml) and carbohydrate

Not only stem cells, but also mature cells, particularly neuroendocrine cells, may develop into tumours: time for a paradigm shift

“…Accordingly, not only the rather benign ECL cell NETs and the highly malignant gastric NECs, 59 , 60 but also a considerable proportion of gastric carcinomas hitherto classified as adenocarcinomas, may origin from the ECL cells based upon numerous studies showing NE cell differentiation in tumour cells. 6 , 41 , 42 , 44 , 58 , 61 – 65 A stem cell origin of these tumour cells would imply that the NE differentiation was due to re-differentiation, which seems unlikely given that mutations often lead to loss and not gain of function. In fact, the NE cancer cells of these tumours are the most differentiated tumour cells, and generally, tumours are classified according to the most differentiated tumour cells.…”