Histological, mucinohistochemical and immunohistochemical features of gastric signet ring cell carcinoma.

Gastric cancer is the fourth most common cancer and the second cause of cancer-related death worldwide . Various types of gastric cancers differ in their epidemiology, pathogenesis, genetic profile and clinical outcome . There has been the overall decline in the total incidence of gastric cancer in the last few decades worldwide, but the decline of signet ring cell (SRC) type of gastric carcinoma has been more gradual and some studies have even reported an increase of SRC type carcinoma . As a result, there are different data about incidence of SRC carcinoma it has been reported that 3.4 – 29% of patients with gastric cancer had SRC type histology and the newest data say that SRC carcinoma accounts for more than 30% of gastric carcinomas in some reported series . Comparing with other types of gastric cancer, SRC gastric carcinoma has a tendency to involve the entire stomach and to extend directly into neighboring organs. It has the poorest prognosis, is more common in females than males and occurs at a comparatively younger age . Although most researchers believe that SRC carcinoma is characterized by poor differentiation, strong invasive tendency and poor prognosis, the clinicopathologic parameters of this type of malignancy are still controversial . Controversial reported data on gastric SRC cancer incidence, prognosis, histogenesis, metastasis, phenotipic histologic and immunohistochemical features, and confusion induced by the presence of morphologic patterns other than the conventional appearance, are the facts that require further investigations . Classifications of gastric carcinoma