Person:

Lauwers, Gregory Y.

Micropapillary carcinoma (MPC) of the stomach is a rare, newly recognized entity, and only 2 patients with this histology have been reported. We investigated clinicopathologic features, expression of mucin (MUC2, MUC5AC, MUC6, CD10) and cytokeratin profiles (CK7 and CK20), epidermal growth factor receptors (EGFR and HER2), prognostic markers (p53 and Ki-67), and outcomes in 11 MPCs of the stomach. The proportion of MPC component ranged from 5% to 70%. Micropapillary features were often found at the deep advancing edge of the tumor. Endolymphatic tumor emboli were found in 10 cases (91%) and lymph node metastases were found in 4 cases (36%). In MPCs, positive expression was observed for Ki-67 (82%), CK7 (73%), EGFR (64%), p53 (64%), MUC5AC (45%), MUC6 (36%), and CK20 (27%). However, MUC2, CD10, and HER2 expression was negative in all cases. In 9 conventional adenocarcinomas and 11 papillary adenocarcinomas with multiple endolymphatic tumor emboli, used as control, positive expression was observed for Ki-67 (100%), CK7 (90%), EGFR (80%), CK20 (70%), p53 (70%), MUC5AC (70%), MUC6 (60%), MUC2 (40%), CD10 (25%), and HER2 (15%). Expression of MUC2, CK20, and the Ki-67 labeling index was significantly higher in control adenocarcinomas as compared with MPCs (P<0.05). However, there was no significant difference in other clinicopathologic features and overall patient survival. Subclassification of MPCs into 2 subgroups according to the proportion of micropapillary component (cut-off value was 20%) failed to find any significant clinicopathologic differences (P>0.05). Although MPCs in other organs show a poor prognosis, this does not seem to be true for gastric MPCs. Further larger studies are necessary to confirm our initial findings.

Gastric intestinal metaplasia can display cytoarchitectural atypia that falls short of qualifying for dysplasia but can be classified as indefinite for dysplasia. Yet few studies have evaluated the prevalence, the morphologic, and biologic characteristics of this variant. Out of a cohort of 554 biopsies with chronic atrophic gastritis and/or dysplasia, we categorized the cases as either (1) simple intestinal metaplasia; (2) intestinal metaplasia with hyperplasia; (3) intestinal metaplasia with basal gland atypia; and (4) gastric dysplasia. The relationship between the subtypes and various clinicopathologic features, mucin immunophenotypes, and biologic characteristics was evaluated. The final cohort consisted of 424 cases of simple intestinal metaplasia, 93 intestinal metaplasia with hyperplasia, 16 intestinal metaplasia with basal gland atypia, and 21 gastric dysplasia. Intestinal metaplasia with basal gland atypia had a prevalence of 2.8% and similar to gastric dysplasia, 3.7%. Both of these lesions were similar in body/fundus distribution (12.5%) and paucity of goblet cells (68.8%). Intestinal metaplasia with basal gland atypia and gastric dysplasia seem to share some biologic similarities but with a lower frequency of alpha-methylacyl-CoA racemase expression (25% versus 62%), p53 expression (6.3% versus 47.6%), and increased Ki-67 index on surface/pit and isthmus in intestinal metaplasia with basal gland atypia. Alternatively, simple intestinal metaplasia and intestinal metaplasia with hyperplasia did not differ statistically with regard to the various characteristics evaluated. We concluded that gastric intestinal metaplasia can be divided into 2 broad categories that are readily defined by cytoarchitectural and biologic characteristics. Based on the characteristics of intestinal metaplasia with basal gland atypia and in keeping with others, we confirm that this subtype could represent a preneoplastic lesion that needs further evaluation.

The diagnosis of gastric epithelial dysplasia, a precursor lesion of gastric adenocarcinoma, is hindered by interobserver variability and by its resemblance to regenerative changes. Loss of cell polarity, a histological feature of gastric epithelial dysplasia, may be difficult to ascertain, especially in the setting of inflammation or injury. A biomarker of cell polarity could be useful in diagnosis of dysplasia, but has not been reported. The Lethal giant larvae (lgl) gene controls apical–basal polarity of epithelial cells in Drosophila, and has properties of a tumor-suppressor gene. Two homologs, lgl1 and lgl2, are present in mammals and lgl2 mRNA is highly expressed in the stomach. The goal of our study was to test the hypothesis that Lgl2 protein expression and/or localization are disrupted in gastric epithelial dysplasia and adenocarcinoma. Routinely processed pathology specimens including 94 benign mucosae of digestive organs, in addition to 36 reactive gastropathy, 57 gastric epithelial dysplasia, and 77 gastric adenocarcinomas, were immunostained for Lgl2 protein. All normal, reactive, and chronically inflamed gastric epithelia showed basolateral Lgl2 staining. Normal esophageal, duodenal, colonic, biliary, and pancreatic duct mucosae, as well as gastric intestinal metaplasia, did not express Lgl2. All but one case each of gastric epithelial dysplasia and adenocarcinoma showed either complete loss of anti-Lgl2 immunoreactivity or diffuse, mostly weak, cytoplasmic staining. Complete loss of immunoreactivity was significantly more often observed in diffuse-type than in intestinal-type adenocarcinomas (79 vs 48%, respectively). Our data suggest that Lgl2 expression is either aberrantly localized or lost in gastric epithelial dysplasia and adenocarcinoma, whereas it is maintained in reactive gastric mucosa. We propose that Lgl2 may be a potential marker to rule out gastric epithelial dysplasia and adenocarcinoma in diagnostic specimens. However, the consistently negative anti-Lgl2 immunoreactivity seen in intestinal metaplasia does not allow differentiation of dysplasia from intestinal metaplasia with reactive change.

In Western countries, distal esophageal adenocarcinoma has outnumbered squamous cell carcinoma because of a dramatic increase in the prevalence of columnar-lined esophagus. Because the relative prevalence of these diseases remains unknown in China, we investigated the histopathology of distal esophageal neoplasm in resection specimens from a high-volume medical center in China. A computerized search of esophageal cancer was conducted in the pathology database between 2004 and 2010. Cancers with epicenter located within 5 cm above the gastroesophageal junction were retained for analysis. Pathology reports were reviewed along with medical, radiologic, and endoscopic records. All histology slides of selected cases were reevaluated (median, 13 per case). Conventional and basaloid squamous cell, adenosquamous, mucoepidermoid, and neuroendocrine carcinomas and esophageal adenocarcinoma were categorized according to the World Health Organization classification of esophageal cancers. The presence of columnar-lined esophagus and other pathologic changes were assessed in cases with residual esophageal mucosa. Among 1101 resections, 204 (19%) qualified for the study. Conventional and basaloid squamous cell, adenosquamous, mucoepidermoid, and neuroendocrine carcinomas and esophageal adenocarcinoma represented 76%, 11%, 3%, 2%, 6%, and 1% of the cases, respectively. Synchronous carcinomas were found in 12% and consisted of primarily squamous cell carcinoma (50%) and proximal gastric adenocarcinoma (38%). Columnar-lined esophagus was detected in 18% of the cases, among which intestinal metaplasia was present in 30% and low-grade dysplasia in 7%. In conclusion, distal esophageal carcinomas in Chinese patients showed a wide histopathologic spectrum with predominant squamous cell carcinoma and rare esophageal adenocarcinoma. Although common, columnar-lined esophagus appears pathogenetically insignificant for most distal esophageal carcinomas.