• mucosa associated lymphoid tissue
• lymphoma
• oesophagus
• primary oesophageal lymphoma
• endoscopic mucosal resection
• monoclonality

A pproximately 40% of all non-Hodgkin's lymphomas occur in extranodal locations. The majority are of the diffuse large B cell type but extranodal marginal zone B cell lymphoma of mucosa associated lymphoid tissue (MALT lymphoma) is the commonest extranodal small B cell non-Hodgkin's lymphoma. Approximately 37% of extranodal lymphomas occur in the gastrointestinal tract and oesophagus.¹ The commonest site is the stomach (23% of extranodal lymphomas) followed by the small intestine (7.5%) and the colorectum (5.5%).¹ Primary lymphoma of the oesophagus is very rare accounting for only three cases in a series of 1467 reported by Freeman and colleagues.¹ The majority of lymphomas that have been reported in the literature date from before the advent of current knowledge about MALT lymphoma, its pathogenesis, molecular genetics, and treatment but in this issue of Gut, Hosaka and colleagues² describe in detail a case of primary oesophageal lymphoma, diagnosed and treated by endoscopic mucosal resection [see 281]. Their …