Mucosa-Associated Lymphoid Tissue Gastric Lymphoma Regression in a Renal Transplant Patient After Conversion of the Immunosuppression to Sirolimus: A Case Report E.P. Lasmar, L.G.V. Coelho, M.F. Lasmar, L.F. Lasmar, P.V. Lima, and A.F. Nogueira ABSTRACT The treatment of B-cell non-Hodgkin lymphoma, the most common posttransplant lympho- proliferative disorder, is not well defined. Herein we have reported a case of gastric mucosa-associated lymphoid tissue (MALT) lymphoma with rapid, persistent, and complete remission after conversion of the immunosuppression from cyclosporine (CsA) to sirolimus (SRL). A 42-year-old woman underwent renal transplantation in 1992 with no major abnormalities until 2006 when a gastroscopy performed to investigate dyspeptic symptoms showed a mixed MALT gastric lymphoma (with low- and high-grade components) associated with the presence of Helicobacter pylori infection. Two therapeutic interventions in a 1-week interval were performed: treatment of the H. pylori infection (omeprazole, amoxicillin, and clarithromycin for 14 days) and modification of the immunosuppression by substitution of CsA and azathioprine (AZA) with SRL. Control endoscopy performed 1 month later showed persistence of H. pylori infection and absence of the gastric tumor. New endoscopies performed at 2 and 7 months after therapy confirmed the absence of neoplasia and H. pylori eradication. Currently, the patient has no complaints, displaying a creatinine value of 1.8 mg/dL and a hemoglobin of 9.4 mg/dL using SRL and ibersatan. SRL has been studied extensively as an anticancer drug, acting as a mammalian target for rapamycin (mTOR) inhibitor. Accumulating data support the role of mTOR in lymphomagenesis. In conclusion, our case of gastric MALT lymphoma in a renal transplant patient displayed a complete remission after alteration of the immunosuppressive scheme with the introduction of SRL. P OSTTRANSPLANT lymphoproliferative disorders oc- cur in 1% to 20% of solid organ transplant recipients, most of them being B-cell non-Hodgkin lymphoma (NHL). 1 The occurrence of this disease in a renal recipient is associated with a major risk of death and a decreased survival rate from 80% to 65% at 5 years. 2 The treatment is not well defined; it carries a significant risk of rejection or loss of renal function. Sirolimus (SRL), a mammalian target for rapamycin (mTOR) inhibitor, has been demonstrated to display antitumor properties in vitro and in vivo. Herein we have reported a case of mucosa-associated lymphoid tissue (MALT) gastric lymphoma regression in a renal transplant patient after conversion from cyclosporine (CsA) to SRL. CASE REPORT A 42-year-old white woman underwent renal transplantation on June 3, 1992 from a sister donor (3 mismatches). She showed no abnormalities during the immediate postoperative period, receiving immunosuppressive treatment with CsA, azathioprine (AZA), and prednisone. An acute rejection episode which occurred in 1994 was controlled with pulse therapy (methylprednisolone, 250 mg  3). In January 2001, she presented with a vaginal papilloma virus infection treated by a reduced AZA dose (from 100 to 75 mg). The patient underwent upper digestive endoscopy on June 7, 2006 due to dyspeptic symptoms. A histological and immunohistochemical diagnosis of mixed MALT gastric lymphoma (with low- and high-grade components) was associated with the presence of Helicobacter pylori infection (Figs 1, 2). Treatment to eradicate From the Hospital Universitário São José, FCMMG/Univer- sidade Federal de Minas Gerais/Hospital Mater Dei, Belo Hori- zonte, Brazil. Address reprint requests to Euler P. Lasmar, Department of Transplantation, Hospital Universitario São José/Mater Dei, Rua Newton 89, Belo Horizonte, Brazil, 30.360-200. E-mail: lasmar@ superig.com.br © 2009 by Elsevier Inc. All rights reserved. 0041-1345/09/$–see front matter 360 Park Avenue South, New York, NY 10010-1710 doi:10.1016/j.transproceed.2009.02.003 Transplantation Proceedings, 41, 959 –961 (2009) 959