A 66-Year-Old Man Presenting with Port-Site Metastatic Gastric Adenocarcinoma 4 Years After Laparoscopic Resection of a Rectal Adenocarcinoma.

BACKGROUND There is a recognized association between synchronous and metachronous colorectal and gastric adenocarcinoma. This report describes a 66-year-old man presenting with port-site metastatic gastric adenocarcinoma 4 years after laparoscopic resection of a rectal adenocarcinoma. CASE REPORT A 66-year-old male rectal cancer survivor presented to the clinic with a painless mass at the previous laparoscopic anterior resection port site. Physical examination revealed a soft port-site mass measuring 5×4 cm. Abdominal CT revealed enlargement of the right rectus abdominis muscle and thickening of the gastric fundus. A biopsy of the right abdominal wall mass revealed metastatic adenocarcinoma. Immunohistochemistry (IHC) testing was positive for cytokeratin 7 (CK7) and CDx2 and negative for cytokeratin 20 (CK20). The possible primary malignancy was upper gastrointestinal, and it was less likely to be colorectal in origin. Subsequently, the upper endoscopy revealed a friable, erythematous gastric mucosa. Biopsy revealed an invasive moderately differentiated gastric adenocarcinoma with positive IHC for CK7 and CDx2 and negative for CK20. The rectal adenocarcinoma pathology slides were reviewed, and IHC testing showed negative CK7 and positive CK20. Patient was known to have multiple comorbidities with poor functional status. The tumor board decision was made to manage him palliatively with best supportive care for the diagnosis of metastatic gastric cancer. CONCLUSIONS This report has presented a case of possible metachronous gastric adenocarcinoma with port-site metastasis following resection of a rectal adenocarcinoma. Clinicians should be aware of the association between synchronous and metachronous colorectal and gastric adenocarcinoma and the challenges associated with the diagnosis.