[Metachronous cancer of the gastro-intestinal tract with signs of endocrine-cell differentiation].

A case of metachronous cancer of gastrointestinal tract is reported. Three poorly differentiated malignant epithelial tumours developed in a 27-year-old patient within three years. They located in the stomach, small and large intestine. Light-microscopically, the tumours were formed mainly of non-differentiated rounded cells with occasional signet ring cells. At electron microscopic examination the presence of mucin granules was confirmed. Moreover, a variable amount of electron-dense endocrine-like granules was found in tumour cells. According to some publications, endocrine differentiation of gastrointestinal cancers is considered to be a poor prognostic feature, hence electron microscopy or special staining when possible can be important in the evaluation of prognosis.