A Case of Coexisting Malignant Lymphoma and Adenocarcinoma Occurring as a Collision Tumor in the Stomach with Malignant Lymphoma of the Tonsil

Tetsuya Naito¹⁾, Satoru Nakagawa¹⁾, Yoshiyuki Ikeda¹⁾²⁾, Kazuhito Yajima¹⁾, Koji Kaneko¹⁾, Shintaro Komukai¹⁾, Manabu Ohashi¹⁾, Tatsuo Kanda¹⁾, Ken Nishikura²⁾ and Katsuyoshi Hatakeyama¹⁾

Division of Digestive and General Surgery, Niigata Graduate School of Medical and Dental Sciences¹⁾
Division of Molecular and Functional Pathology, Department of Cellular Function, Niigata Graduate School of Medical and Dental Sciences²⁾

We report a rare case of coexisting malignant lymphoma and adenocarcinoma occurring as a collision tumor in the stomach with malignant lymphoma of the tonsil. A 62-year-old man reporting swelling of the left tonsil was diagnosed with malignant diffuse large B cell lymphoma of the left tonsil. Gastric carcinoma was found in a systemic checkup following this diagnosis. A depressed lesion was found at the posterior wall of the lower body of the stomach, and endoscopic biopsy showed well differentiated adenocarcinoma, necessitating distal gastrectomy combined with D2 lymph node dissection. Histologically, the resected specimen showed a collision tumor in which carcinoma (tub1, m) contacted malignant lymphoma (diffuse large B cell type, sm2), but without nodal metastasis. The postoperative course was uneventful. A CyclOBEAP regimen (cyclophosphamide, vincristine, bleomycin, etoposide, doxorubicin, prednisolon) for malignant lymphoma of the left tonsil was conducted elsewhere 1 month after surgery, after which the man entered complete remission. The patient remains alive with recurrence-free 14 months after surgery.

Key words
malignant lymphoma, early gastric cancer, collision tumor

Reprint requests
Tetsuya Naito Division of Digestive and General Surgery, Niigata Graduate School of Medical and Dental Sciences
1-757 Asahimachi-dori, Niigata, 951-8510 JAPAN

Accepted
March 24, 2004

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