Effectiveness of Chemothrapy Against Pancreatic MALT Lymphoma: Report of a Case

Ken-ichi Okada, Toshihide Imaizumi, Masahiro Matsuyama, Shoichi Dowaki, Kosuke Tobita and Hiroyasu Makuuchi

Department of Surgery, Tokai University School of Medicine

An asymptomatic 55-year-old man seen for further evaluation of a pancreas head mass was found in ultrasonography (US) to have a low echoic 46×38×28 mm mass. Dynamic computed tomography (CT) and magnetic resonance imaging (MRI) showed an enhanced mass. Diffusion MRI demonstrated a high signal tumor presumably rich in cells. Angiography showed no evidence of vascular invasion except for compression to portal veins. Differential diagnosis included tumor-forming pancreatitis, nonfunctioning islet cell tumor, pancreatic lymphoma, invasive ductal carcinoma, and solid and pseudopapillary tumor. Laparotomy for tissue biopsy showed atypical lymphoid cell infiltration suggesting possible malignant lymphoma. The definitive diagnosis, based on histopathological examination of permanent sections, including immunohistochemical staining, was pancreatic mucosa-associated lymphoid tissue (MALT) lymphoma. Eight sessions of chemotherapy reduced the mass totally, suggesting a complete response. Primary pancreatic lymphoma is a rare, basically systemic disease, making chemotherapy the first choice. Pancreatic MALT lymphoma is a low-grade B cell lymphoma, for which excessive surgery should be avoided if possible, by careful evaluation of biopsy. Biopsy should be conducted in all procedures in case preoperative graphical findings are not consistent with typical findings for invasive ductal pancreatic carcinoma.

Key words
pancreatic mucosa-associated lymphoid tissue lymphoma, biopsy, chemotherapy

Reprint requests
Ken-ichi Okada Department of Surgery, Tokai University, School of Medicine
143 Shimokasuya, Isehara, 259-1193 JAPAN

Accepted
February 18, 2009

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