原発性胃悪性リンパ腫と全身性悪性リンパ腫症における胃浸潤との鑑別

Differential Diagnosis in Primary Gastric Malignant Lymphoma and Gastric Infiltration of Systemic Malignant Lymphoma

　胃の悪性リンパ腫のX線および内視鏡的診断規準は近年ようやく定着してきたものの，なお，非定型的な症例では，胃癌との鑑別が困難な例も少なくない．臨床的に確定診断を下すために有用な生検診断も，胃癌のそれに比し，診断成績が劣る事実も否定できない．

　他方，胃の悪性リンパ腫には，胃に原発する病変のほかに，全身性の悪性リンパ腫症における一部分症として，胃に病変が存在する場合がある．また，胃に原発した悪性リンパ腫も他臓器に転移し，末期には全身性の悪性リンパ腫症に発展する場合がある．

　Comparing primary gastric malignant lymphoma with gastric lesion of systemic malignant lymphoma, the following morphological differences can be seen.

　1) The systemic malignant lymphoma tends to have interrupted multiple gastric lesions. Especially multiple small lesions in the stomach are the characteristic feature of the systemic malignant lymphoma. On the other hand, primary gastric malignant lymphoma may have the similar lesions but they are accessary lesions and apart from the main one.

　2) Superficial spreading type like Ⅱc lesion is more common in primary gastric lymphoma. However, the systemic malignant lymphoma may have the similar gastric lesion as primary gastric lymphoma and it may be impossible to differentiate only from the morphological appearance. Therefore, we have to make a differential diagnosis by clinical course or spreading range of the lymphoma.

　In systemic malignant lymphoma, endoscopic diagnosis of the gastric lesion is usually not so difficult. However, in primary gastric lymphoma it is not so easy and we should be very cautious to make its diagnosis by biopsy.

　Since malignant lymphoma responds quite well to chemotherapy and its macroscopic morphology changes easily, we emphasized the necessity of performing endoscopy as well as histological evaluation of biopsy specimen prior to the chemotherapy to see whether the systemic malignant lymphoma has gastric invasion or not.