Concurrence of primary gastric
adenocarcinoma and
lymphoma have been described very rarely in the
literature; its
incidence is estimated at 0.08%. To our
knowledge, there are no
reports about a collision
tumor comprising early
gastric cancer and
diffuse large B-cell lymphoma from the same lesion. The term "collision
tumor" refers to the coexistence of two or more histologically distinct
tumors within the same mass with no histologic admixture. A 76-year-old man complained of a 5-month-
history of
dyspepsia, and underwent
esophagogastroduodenoscopy. Endoscopic findings showed a nodular, round, flat mass lesion in the upper body, therefore we performed
endoscopic submucosal dissection (ESD). Pathologic findings revealed a well-differentiated
adenocarcinoma accompanied by
diffuse large B-cell lymphoma without evidence of
Helicobacter pylori infection. Conventional CT and
PET-CT scans revealed metastatic
lymph nodes in the
parotid gland,
submandibular gland, maxillary gland and the inguinal regions. The pathogenesis of a collision
tumor comprising two different
cancers is not well understood. In addition, there are no established
treatment guidelines in this series. In the current case, the
patient underwent ESD for the removal of
adenocarcinoma concomitantly with
chemotherapy for the management of metastatic
lymphoma.