The Differential Diagnosis of Malignant Lymphoma and Reactive Lymphoreticular Hyperplasia of the Stomach Using Endoscopic Ultrasonography

Abstract: It is difficult to differentiate between reactive lymphoreticular hyperplasia (RLH) and malignant lymphoma (ML) even with an endoscopic biopsy. We performed endoscopic ultrasonography (EUS) examination on 25 cases histologically diagnosed as being RLH or ML. We classified their EUS findings into three types; protruding, wall‐thickening and superficial types, and examined their ultrasonographic findings. Of the four cases classified as being the protruding type (ML 3, RLH 1), disruption of the third layer was seen in the cases of ML, while it was preserved in the case of RLH. All nine cases of the wall‐thickening type were ML. Twelve cases were classified as being the superficial type (ML 6, RLH 6). Of the five cases of this type without ulcerative changes, thickening of the second layer of the low echoic homogeneous pattern (“Loss of original mucosal structure: OMS”) was seen in all two cases of ML, while the second layer was dotted with low echoic granular particles and looked grossly heterogeneous (“Granular pattern”) in all three cases of RLH. In the other seven cases the lesion looked like an advanced tumor due to ulcerative changes. From observations of the surrounding nonulcerative area, “Loss of OMS” was seen in three of four cases of ML, while a “Granular pattern” was seen in all three cases of RLH. Six of seven cases with only the “Granular pattern” were RLH, and all 16 cases with only the “Tumorous pattern” were ML. Of the two cases with the “Combined pattern” which had the “Tumorous pattern” in the central area and “Granular pattern” in the peripheral area, one was ML and the other was RLH. EUS is thought to be a useful diagnostic technique which provides us with important information to differentiate between ML and RLH.