Mucosal endocrine cell micronests and single endocrine cells following neo-adjuvant therapy for adenocarcinoma of the distal oesophagus and oesophago-gastric junction

Abstract

Aims: To determine the frequency of endocrine cell micronests (ECM) and single endocrine cells (SEC) within the glandular mucosa of the distal oesophagus and oesophago-gastric junction (OGJ) following neo-adjuvant therapy for adenocarcinoma. Methods: The resection specimens from 11 patients with adenocarcinoma of the distal oesophagus or OGJ who had undergone pre-operative chemotherapy or chemoradiotherapy (CRT) were reviewed and stained immunohistochemically for cytokeratin and chromogranin. The presence of ECM and/or SEC within the mucosa adjacent to the tumour was noted, and the results correlated with the extent of tumour regression. The corresponding pre-treatment endoscopic biopsies were reviewed in 6 cases and the results were also compared to 10 tumour resections from patients with no history of neo-adjuvant treatment. Results: ECM and/or SEC were identified in 8/11 resection specimens after chemotherapy or CRT. The endocrine cells were typically located within the deep lamina propria or muscularis mucosae and were associated with varying degrees of glandular atrophy and inflammation. The appearances were most consistent with endocrine cell preservation (pseudo-hyperplasia) following treatment. Isolated endocrine elements were not seen in the pre-treatment biopsies, while rare SEC without ECM were identified in only 2/10 control resection specimens. Conclusions: Endocrine cell pseudo-hyperplasia may be seen within atrophic glandular mucosa following neo-adjuvant therapy of distal oesophageal/ OGJ adenocarcinomas. The changes are analogous to those seen in chronic atrophic gastritis and should not be misinterpreted as those of residual tumour.