Very Well Differentiated Gastric Cancer of Intestinal Metaplasia-Type: A Systemic Analysis
Tetsuo Ushiku, Shinichi Ban, Thomas Arnason, Tsunekazu Hishima, Masashi Fukayama, Gregory Y Lauwers. Massachusetts General Hospital, Boston, MA; University of Tokyo, Tokyo, Japan; Saiseikai Kawaguchi General Hospital, Saitama, Japan; Tokyo Metropolitan Komagome Hospital, Tokyo, Japan
Background: Very well differentiated gastric adenocarcinoma of intestinal metaplasia-type (VWDAIM) is a rare variant characterized by morphologic differentiation towards intestinal metaplasia (IM) and low-grade cytologic atypia. Because it mimics IM, a definite biopsy diagnosis is challenging. Small series have been published, but detailed diagnostic criteria and clinical behavior are not fully established.
Design: Slides from the resection specimens of 21 cases of VWDAIM were reviewed and their cytoarchitectural features recorded. Forty histologic pictures of benign IM and VWDAIM were also assessed by a blinded independent reviewer to determine the sensitivity & specificity of the diagnostic features of malignancy. Pre-resection biopsies from 19 cases were also evaluated.
Results: Characteristic architectural features of VWDAIM were branching (100%), tortuous (95%), anastomosing (95%), distended (90%), abortive (81%), spiky (76%), and budding (71%) glands. Cytologic atypia was mild in all cases (Figure 1). Sensitivity and specificity of these features for malignancy are shown in Table 1.
|Findings||VWDAIM (n=20)||IM (n=20)||p-value||Sensitivity||Specificity||Odds Ratio|