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P1299 - Stomach Where the Sun Don’t Shine: A Rare Case of Gastric Adenocarcinoma Metastasizing to the Colon

Monday, October 28

10:30 AM - 4:15 PM

Location: Exhibit Halls 3 and 4 (Street Level)

Presenting Author(s)

TH

Trevor Houston, DO

Las Vegas, Nevada

Trevor Houston, DO¹, Diego Lim, MD, MPH², Nevene Andraws, MD³, Prashanth Vennalaganti, MD³

¹University of Nevada Las Vegas School of Medicine, Las Vegas, NV; ²University of Kansas Medical Center, Kansas City, KS; ³Kansas City VA Medical Center, Kansas City, MO

Introduction: Gastric cancer has been known to have a poor prognosis worldwide. It frequently leads to a metastatic disease, but rarely to the colon.

Case Description/Methods: A 73-year old male presented for a routine surveillance colonoscopy. He reported new onset constipation over the last 6-8 months that was not relieved by over-the-counter laxatives. He was found to have a stricture approximately 30 cm from the anal verge (Fig 1). This stricture was not seen on previous colonoscopy in 2014. He had a history of gastric adenocarcinoma 4 years ago, underwent a subtotal gastrectomy followed by chemotherapy and radiation and was closely followed in the oncology clinic. In addition, he also had a gastrointestinal stromal tumor (GIST) in the stomach. Histopathology was consistent with gastric adenocarcinoma (Fig 2). Widespread metastatic disease was found on PET scan (Fig 3).

Discussion: Although gastric cancer metastasizes to the liver, peritoneum and distant lymph nodes commonly, colon metastasis is rare and even rarer is sigmoid metastasis. We report a case of a patient with a change on bowel habits and was found to have gastric adenocarcinoma that has metastasized to the sigmoid colon causing a structuring lesion. In addition, both gastric adenocarcinoma and a concurrent GIST have been reported in literature. It has been suggested that C-KIT or PDGFR-a mutations can lead to both cancer types but more information on this subject is lacking in current literature. It appears though that having both types of cancers do not significantly influences symptoms or disease outcome.

Figure 1: Sigmoid stricture on colonoscopy, approximately 30cm from anal verge

Figure 2: Infiltrating adenocarcinoma (A) Low power view showing infiltrating malignant glands (red arrow) within normal colonic mucosa (arrow head). (B) CK7 immunohistochemical stain highlights tumor cells while the normal colonic mucosa is negative. (C) CK20 immunohistochemical stain is negative in the tumor cells while the normal colonic mucosa is staining.

Figures 3: PET scan results with hyper-metabolic activity not only in the sigmoid but in the liver, small bowel, large bowel and mesentery as well suggesting wide spread metastases.

Disclosures:

Trevor Houston indicated no relevant financial relationships.

Diego Lim indicated no relevant financial relationships.

Nevene Andraws indicated no relevant financial relationships.

Prashanth Vennalaganti indicated no relevant financial relationships.

Citation: Trevor Houston, DO; Diego Lim, MD, MPH; Nevene Andraws, MD; Prashanth Vennalaganti, MD. P1299 - STOMACH WHERE THE SUN DON’T SHINE: A RARE CASE OF GASTRIC ADENOCARCINOMA METASTASIZING TO THE COLON. Program No. P1299. ACG 2019 Annual Scientific Meeting Abstracts. San Antonio, Texas: American College of Gastroenterology.