title: Colliding gastric and intestinal phenotype well-differentiated adenocarcinoma of the stomach developing in an area of MALT-type lymphoma.
abstract: A 73-year-old man presented with an abnormal gastric shadow during a check-up of atomic bomb survivors. Radiological examination and endoscopy of the upper gastrointestinal tract revealed a protruding tumor, type 0-I+IIa, on the lesser curvature of the midstomach. An initial diagnosis of early gastric cancer was made and a segmental gastrectomy was planned. However, distal gastrectomy with D3 lymph node dissection was necessary, because intraoperative frozen section showed that the paraaortic lymph nodes (N3) were positive for cancer. The tumor in the resected specimen was, microscopically, a well-differentiated tubular adenocarcinoma (tub1) with pT2 (MP), pN3, ly2, and v1, in final (f) stage IV. The tumor cells of the type 0-I segment appeared as gastric phenotype and those of the type 0-IIa segment as intestinal phenotype. The border between the two was distinct. The tumor had focally invaded the muscularis propria where only the gastric phenotype was shown and the histological type became less differentiated. Thus, special attention should be paid to possible unexpected deep-wall invasion and lymph node metastasis in well-differentiated adenocarcinomas of the gastric phenotype. Further, in this patient, diffusely proliferating low-grade lymphoma was also observed incidentally in the gastric mucosa within and around the carcinoma. This was diagnosed as mucosa-associated lymphoid tissue (MALT)-type lymphoma with aberrant expression of BCL10. Finally, this case was considered to be a colliding gastric and intestinal phenotype well-differentiated adenocarcinoma of the stomach developed in an area involved by MALT-type lymphoma. Because no Helicobacter pylori was detected throughout the mucosae and the patient had no history of its infection, the three tumors may have developed under the same conditions as those seen in Helicobacter pylori infection, but without this infection.
authors.affiliation: Division of Gastroenterological Surgery, Cancer Institute Hospital, Tokyo, Japan.
authors.forename: Mitsukuni
authors.initials: M
authors.lastname: Suenaga
authors.forename: Kei-ichiro
authors.initials: K
authors.lastname: Ohta
authors.forename: Masataka
authors.initials: M
authors.lastname: Toguchi
authors.forename: Takahiro
authors.initials: T
authors.lastname: Sato
authors.forename: Shigekazu
authors.initials: S
authors.lastname: Ohyama
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Tetsuichiro
authors.initials: T
authors.lastname: Muto
authors.forename: Akio
authors.initials: A
authors.lastname: Yanagisawa
authors.forename: Yo
authors.initials: Y
authors.lastname: Kato
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology* / Q000601:surgery; D000368:Aged; D005743:Gastrectomy; D006801:Humans; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D018442:Lymphoma, B-Cell, Marginal Zone / Q000473:pathology* / Q000601:surgery; D008297:Male; D009367:Neoplasm Staging; D009378:Neoplasms, Multiple Primary; D010641:Phenotype; D013274:Stomach Neoplasms / Q000473:pathology* / Q000601:surgery