P1562 - A Rare Case of Metastatic GIST Presenting as a Renal Mass and Recurrent Gastrointestinal Bleeding

Dhruv Patel, MD, Kimberly Chaput, DO
St. Luke's University Health Network, Fountain Hill, PA

Introduction: Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors derived from interstitial cells of Cajal (ICCs). GISTs can originate from anywhere in the gastrointestinal (GI) tract from the esophagus to anus, with roughly 50% located in the stomach. In rare cases they can be observed in the peritoneum, omentum, mesentery or other organs such as the liver, pancreas, uterus, and ovaries. Most commonly GISTs metastasis to the liver or abdominal membranes. Stromal tumors originating from outside the gastrointestinal tract are described as extragastrointestinal stromal tumors and cases have been reported from the gallbladder, abdominal wall, liver, pancreas.

Case Description/Methods: A 63-year-old male with history of depression presented with abdominal pain, melena, and acute normocytic anemia. He underwent abdominal ultrasound and was found to have a large complex heterogeneous mass within his right kidney measuring 21.7 x 13.3 x 19.0 cm suspicious for malignancy. Patient underwent upper endoscopy and was noted to have a small non-bleeding Forrest Class III gastric ulcer and duodenal ulcer. Biopsies of both ulcers were negative for malignancy. Patient underwent kidney biopsy showing malignant spindle cell tumor (c-kit +) with extensive necrosis, consistent with GIST. Patient re-presented two months later with repeat upper GI bleeding and underwent repeat endoscopy which showed a new Forrest Class IIB large, cratered, malignant-appearing ulcer in the duodenum which was not amenable to endoscopic intervention. He underwent IR embolization of his inferior pancreaticoduodenal artery with resolution of bleeding. Concern was that patient’s renal mass had possibly eroded into duodenum causing recurrent GI bleeding. He was evaluated by oncology with plan to start neoadjuvant chemotherapy with imatinib prior to surgical excision.

Discussion: GISTs are the most common mesenchymal neoplasms of the gastrointestinal tract. It is rare for GISTs to present as a renal mass. One case report describes renal origin GIST, however it is an unlikely source for the tumor. Our patient demonstrates a unique case of renal mass believed to be primary source for malignancy, in reality representing metastasis from suspected duodenal origin. Patients presenting with large retroperitoneal or renal masses with recurrent GI bleeding should have GISTs and malignant metastasis on the differential. Sequential endoscopy for tissue diagnosis may be warranted to aid in accurate identification of lesion primary.


Figure: (A) Second portion duodenal ulcer - Forrest class III ulcer
(B) Increasing duodenal ulcer with no active bleeding
(C) Active bleeding within duodenal ulcer with blood clots
(D) Right renal mass occupying large portion of renal circumference


Disclosures:
Dhruv Patel indicated no relevant financial relationships.
Kimberly Chaput indicated no relevant financial relationships.


Dhruv Patel, MD, Kimberly Chaput, DO. P1562 - A Rare Case of Metastatic GIST Presenting as a Renal Mass and Recurrent Gastrointestinal Bleeding, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.