Hindawi Publishing Corporation Case Reports in Gastrointestinal Medicine Volume 2013, Article ID 930918, 4 pages http://dx.doi.org/10.1155/2013/930918 Case Report Precursor B Lymphoblastic Lymphoma Involving the Stomach Masaya Iwamuro, 1,2 Yoshinari Kawai, 1 Yasuhide Yamawaki, 3 Katsuyoshi Takata, 4 and Kazuhide Yamamoto 2 1 Department of Gastroenterology, Onomichi Municipal Hospital, Onomichi 722-8503, Japan 2 Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama 700-8558, Japan 3 Department of Internal Medicine, Onomichi Municipal Hospital, Onomichi 722-8503, Japan 4 Department of Pathology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama 700-8558, Japan Correspondence should be addressed to Masaya Iwamuro; iwamuromasaya@yahoo.co.jp Received 5 May 2013; Accepted 4 June 2013 Academic Editors: P. Abraham, O. I. Giouleme, I. M. Leitman, and S. Nomura Copyright © 2013 Masaya Iwamuro et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Precursor B lymphoblastic lymphoma is a high-grade neoplasm arising from precursor lymphocytes of B-cell lineage. Extranodal sites such as the skin and bone are ofen involved, but gastrointestinal lesions of this disease are rarely encountered. Due to the infrequency, macroscopic forms of the gastrointestinal lesions have not been fully described. In this report, we present a case of precursor B lymphoblastic lymphoma involving the stomach, pancreas, bone, and bone marrow. Esophagogastroduodenoscopy showed multiple fat elevated lesions with irregular mucosa in the stomach. 1. Introduction Precursor B lymphoblastic lymphoma is a neoplasm of lymphoblasts committed to the B-cell lineage [1]. Histolog- ically, neoplastic cells are composed of small- to medium- sized lymphoid cells with blastic nuclear chromatin and a high mitotic rate [2]. In immunohistochemical analysis, the disease is characterized by positive staining for terminal deoxynucleotidyl transferase (TdT), in addition to B-cell antigens [1]. Clinically, extranodal sites such as the skin and the bone are frequently afected. On the other hand, infltration of the neoplastic cells into the gastrointestinal tract is relatively infrequent. Terefore, the endoscopic man- ifestation of this disease has not been fully revealed to date. We recently treated a patient with precursor B lym- phoblastic lymphoma who had extensive extranodal involve- ment in the stomach, pancreas, bone, and bone marrow. Herein we report the case and illustrate its characteristic endoscopic features. 2. Case Presentation An 85-year-old Japanese female presented to Onomichi Municipal Hospital with facial pain and lockjaw due to a swelling of the lef temporomandibular joint. Her pain had started one year previously. Te patient went to another clinic at that time, but the cause of her symptoms was not revealed. Two months prior to her visit to our hospital, she went to a dental clinic because lockjaw had appeared. Subsequently, swelling of the temporomandibular joint worsened and she was referred to our hospital for further investigation and treatment. She had been taking antihypertensive agents for hypertension and antifungal agent for nail tinea of the feet. Te patient had no previous history of hematopoietic or gastrointestinal diseases. Physical examination revealed no abnormalities except for a mass lesion in the lef temporomandibular joint. Tere was no evidence of hep- atosplenomegaly or peripheral lymphadenopathy. Labora- tory fndings revealed elevated levels of lactate dehydrogenase (LDH) to 232 IU/L (normal range: 104–203 IU/L) and soluble