Myeong-Cherl Kook, pathologist, Natiional Cancer Center, Goyang, South-Korea

Biography

Dr. Kook is Researcher and Staff Pathologist in National Cancer Center. He graduated from Seoul National University College of Medicine in 1992 and received training at Seoul National University Hospital. He acquired a certificate of pathologist in 1997 and received his PhD in 2001 from Seoul National University. From 2000 to 2003 he worked at Jeju National University and since 2004 at the National Cancer Center.
He is an expert on gastric cancer pathology. He have conducted research on the classification and prognostic factors of gastric cancer through morphological and molecular analysis. He have also conducted pathology protocol planning and pathology analysis in several important clinical trials about Helicobacter eradication for cancer prevention, sentinel node navigation surgery and endoscopic submucosal dissection of UD-type gastric cancer.

Summary of presentation

Poorly cohesive (PC) gastric cancer (GC) is composed of neoplastic cells that are isolated or arranged in small aggregates without well-formed glands. Among PC GC, Signet ring cell (SRC) carcinoma is composed of neoplastic cells having a large amount of intracellular mucin with eccentrically placed nucleus. GC composed of PC tumor cells other than SRC is non-SRC type PC GC, which is called as PC carcinoma not otherwise specified (PCC NOS). PC GC is classified as a diffuse type according to Lauren classification. Pure SRC carcinoma is uncommon and the morphologies of tumor cells often change to non-SRC type. Therefore, SRC carcinoma and PCC NOS are differentiated based on the composition ratio of the two cellular components. Another diagnostic problem is the distinction from some types of tubular poorly differentiated (PD) adenocarcinomas. Currently, in the WHO classification, PD adenocarcinomas only include the Lauren indeterminate type GCs that form large solid structures. However, many pathologists have also diagnosed diffuse type GCs with small cohesive structures as PD adenocarcinomas. There are reports that the aggressiveness varies depending on the tumor cell composition of PC GC. In the case of SRC carcinoma, the frequency of lymph node metastasis is very low, while in the case of tumors having small cohesive structures (PD component), the frequency of lymph node metastasis increased. Therefore, it may be clinically important to distinguish tumor cell components in PC GC.