Gastric dysplasia-like epithelial atypia associated with chemoradiotherapy for esophageal cancer: a clinicopathologic and immunohistochemical study of 15 cases.

Preoperative chemotherapy combined with radiotherapy (chemrad) is a common type of neoadjuvant treatment for esophageal adenocarcinoma or squamous cell carcinoma. The purpose of this study was to describe the clinical, histologic, proliferative (MIB-1), and oncogenetic (p53) features of 15 patients with gastric dysplasia-like epithelial atypical changes associated with preoperative chemrad for esophageal cancer. Two of these cases were initially misinterpreted as dysplasia, which led to partial gastrectomy. The findings were compared with 12 age- and sex-matched patients with known gastric dysplasia. Cases with gastric dysplasia-like epithelial atypia were significantly associated with a flat gross appearance, a patchy distribution, foveolar and gland involvement, surface maturation, an open nuclear chromatin pattern with prominent nucleoli, retention of nuclear polarity, mitoses confined to the pits, lack of atypical mitoses, cytoplasmic hypereosinophila and/or vacuolization, a lack of association with intestinal metaplasia, and finally, irregular glandular microcystic change, in comparison to the dysplasia controls. Furthermore, the study cases showed MIB-1 positivity restricted to the deep foveolar epithelium and an absence of p53 staining in 14 of 15 cases, in contrast to the dysplasia controls, in which MIB-1 stained both the deep and superficial foveolar epithelium and surface epithelium, and p53 was positive in all cases (100%). In summary, a number of histologic and immunohistochemical features may distinguish gastric dysplasia-like epithelial atypia associated with chemrad for esophageal cancer from true dysplasia. Pathologists should be aware of this entity and its histologic and immunohistochemical features to avoid misinterpretation and prevent unnecessary treatment.