Hematologists Should Order Endoscopic Examination to Specific Gastroenterologists Being Knowledgeable of Malignant Lymphoma in Case of Endoscopic Check-up of Gastrointestinal Malignant Lymphoma
Authors: Yamasaki Takuji , Yahagi Yuichi 
Published: October 2019

Abstract
(Background and aim)
Malignant lymphoma (ML) of the stomach is a most popular lymphoma of the gastrointestinal tract. Especially we often see gastric MALT lymphoma in cases of positive H. pylori (HP) infection, but also find out HP negative gastric MALT lymphoma. Since gastric carcinoma (GC) is more common disease rather than gastric MALT lymphoma, typical endoscopic diagnostic characteristics of GC are established on usual endoscopic examination. On the other hand, diagnostic characteristics of gastric MALT lymphoma on usual endoscopy have not been established for most of gastroenterologists. Actually endoscopic characteristics of gastric MALT lymphoma are not so common for many gastroenterologists. By the way, even if check-up endoscopy of doubtful gastric ML cases, most of hematologists maybe order endoscopic examination as same as other screening endoscopic examination. Is that really all right with you? Our aim of this study is to estimate of the difficulty on diagnosis of gastric MALT lymphoma for gastroenterologists (specialist of ML and non-specialist of ML) on usual endoscopic examination. We sought the ideal ordering of endoscopic examination for hematologists.
(Methods) We investigated a total of 21 gastric MALT lymphoma cases in our hospital. We estimated total number of endoscopic examinations to achieve diagnosis of gastric MALT lymphoma on endoscopically and histologically. In addition, we had analyzed the difference of abilities to diagnose of gastric MALT lymphoma between specialist of ML and non-specialist of ML on endoscopic examinations using past endoscopic profiles.
(Results) Surprisingly, average total number of endoscopic examinations up-to diagnose gastric MALT lymphoma was 3.4 times (from 1 to 7 times) on whole endoscopies. Though average total number of endoscopic examinations of specialist of ML was 1.2 times, on the other hand average total number of endoscopic examinations of non-specialist of ML was 5.4 times. It took so long time to diagnose some cases of gastric MALT lymphoma after first appearance of lymphoma lesions on non-specialist of ML. There was a significant difference between specialist of ML and non-specialist of ML on average total number of endoscopic examinations (p<0.05). Major reason of misdiagnosis was insufficient recognition of endoscopic appearances of ML by gastroenterologists. The representative appearance of gastric MALT lymphoma lesions were erosions, ulcers and surface irregularities. Since these lesions are also appeared as typical appearances of GC and gastritis, most of non-specialist of ML cannot distinguish the difference of GC, ML and gastritis due to those similarities. For example, even if typical ML cases, non-specialist of ML could not diagnose repeatedly, but specialist of ML could diagnose minimal lesions of ML at first endoscopy. Since HP positive gastric MALT lymphoma was especially similar to gastritis and GC on endoscopic findings, most of non-specialist of ML could not diagnose exactly. On the other hand, HP negative gastric MALT lymphoma have been diagnosed more easily rather than HP positive gastric MALT lymphoma.
(Conclusion) There was significant difference of ability to diagnose gastric MALT lymphoma between specialist of ML and non-specialist of ML. Therefore, hematologists should order endoscopic examination to specific gastroenterologists being knowledgeable of malignant lymphoma in case of endoscopic check-up of gastrointestinal malignant lymphoma.

Disclosures
No relevant conflicts of interest to declare.