Glowing Green: Case report of Indocyanine Green uptake in Gastrointestinal Stromal Tumors

Pearl Ma, MD, Prashanth Navaran, MD, Babak Eghbalieh, MD, FACS. University of California-Fresno Surgery

Introduction:

The use of indocyanine green (ICG) fluorescence imaging during robotic assisted laparoscopy has been shown to be helpful in identifying critical structures during robotic gastrointestinal resections and biliary structures during cholecystectomies. Recently, we have noticed an uptake of ICG particularly by gastrointestinal stromal tumors (GIST) which aids identification and dissection of these submucosal masses. We report two cases of ICG uptake in GIST tumors in robotic-assisted laparoscopic partial gastrectomies.

Case Report:

The first patient is a 65-year old woman with a previous history of partial gastrectomy for a prior benign tumor of unclear etiology presented with 2.0 submucosal tumor in the proximal gastric body along the lesser curvature. Workup included EGD, EUS and a CT scan of her abdomen all of which revealed no locoregional spread or distant metastases with an additional biopsy confirming GIST tumor. Our second patient is a 59 year old woman with HIV and intermittent bleeding from a 2.5 cm at the gastroesophageal junction.

Both patients underwent a diagnostic laparoscopy with extensive lysis of adhesions and robotic assisted laparoscopic identification of this GIST tumor. 10 mg of 25 ml solution reconstituted ICG solution was injected intravenously. With the use of Firefly fluorescence imaging for the Da Vinci system, the mass was quickly identified extraluminally and also within the lumen. The tumor was dissected off the mucosa and borders were delineated well under florescence imaging to achieve adequate margins. Final pathology confirmed negative surgical margins. Both patients did well and remained tumor free for one year post operatively.

Discussion:

GIST are the most common intestinal mesenchymal tumors and most often occur in the stomach. Without distant metastasis, surgical resection with a 1-2 cm margin is therapy of choice. GIST tumors have been reported in the literature amenable to laparoscopic and robotic resection with good short term outcomes. With the use of robotic surgery and EndoWrist technology, there is improved ability to manipulate tissue with better dexterity, steady traction, and precise dissection.

With intraluminal growth, GIST tumors may be difficult to identify intraoperatively. ICG has been demonstrated to be useful as an intraoperative real time diagnostic tool with wide applications including sentinel lymph node mapping of breast and gastric cancer, visual assessment of biliary ducts, and microvascular circulation in reconstructive free flaps. It binds to plasma proteins and produces an excitation wavelength maximum at 840nm. Once the the fluorescence signals are detected, these are transmitted to the monitor and lesions appear as spots emitting clear fluorescence.

To our knowledge, ICG has not been previously reported in the literature as an adjunctive tool for surgical resection of GIST tumors. These tumors appear hypervascular on fluorescence and can cut down operative time by quickly identifying these lesions and delineate borders for adequate margins. We have applied the use of this technology with robotic assisted laparoscopy for successful resection of GIST tumors.