Dual tracer functional characterization of metastatic gastric carcinoid
A 32-year-old man presented with features of abdominal pain and enlargement of 6 months duration. Clinical examination revealed a massively enlarged liver reaching up to the umbilicus with no other positive clinical findings. Biochemical examination, liver function tests, and viral markers were within normal limits except for an elevation of serum alkaline phosphatase. A preliminary high-resolution dual phase computed tomography (CT) revealed a grossly enlarged liver with multiple enhancing hypodense lesions suggestive of hypervascular secondaries and thickening of the greater curvature of the stomach []. An upper gastrointestinal (UGI) endoscopy done during the same time revealed a 3 cm × 2 cm ulcer with rolled up edges along the greater curvature of the stomach. FNAC from one of the liver SOL revealed features of neuroendocrine tumor (NET) with positive immunohistochemistry and a Ki-67 index of 40-50%, following which the patient underwent positron emission tomography/CT (PET/CT) using two different radiotracers with differing imaging perspectives: 18F-fluorodeoxyglucose (18F-FDG) (a metabolic tracer) and 68Gallium-DOTA-NOC (somatostatin receptor expressing tumor seeking tracer).\n18F-FDG PET/CT revealed multiple hypodense lesions in liver with focally increased radiotracer uptake, suggestive of poorly differentiated secondaries with high metabolic activity, which was earlier proven on FNAC from a liver SOL [] while foci of increased tracer uptake in a soft-tissue mass at the greater curvature of the stomach was seen on a 68Ga-DOTA-NOC PET/CT scan suggesting a well-differentiated primary somatostatin receptor expressing NET in addition to regional lymph node involvement while the liver lesions showed no tracer uptake []. A gastric biopsy later confirmed this finding (well-differentiated NET; Ki-67 index-2%) []. Based on a combination of these findings the patient was deferred from surgery and instead underwent chemotherapy protocol with etoposide and cisplatin, following which he went into a near total clinical and radiological remission []. The patient however had recurrence later on and despite aggressive treatment even including a bone marrow transplant, he succumbed to his disease.