Endocrine Abstracts

Introduction: Gastrinomas are rare neuroendocrine tumours (NETs) that arise from enterochromaffin-like cells and produce gastrin. Most are discovered in the duodenum and pancreas. The clear cell type of renal cell carcinoma (RCC) is known for the expression of gastrin-releasing peptide receptor (GRP-R) and some studies have shown GRP can stimulate tumor cell proliferation and neoangiogenesis. Therefore, we present a case with metachronous development of renal cell carcinoma and gastrinoma.

Case presentation: A 55-year-old obese, hypertensive female patient with a history of renal cell carcinoma (histopathology: Grawitz tumour grade 2) treated with surgery, radiotherapy and interferon at the age of 36 years old, presents with the suspicion of a neuroendorine tumour. SPECT/CT scan identified a possibly neuroendocrine tumour localised in the ileum and the blood tests revealed a gastrin level of 30 times x upper limit of normal (ULN) and chromogranin A 2.11 times x ULN. All other neuroendocrine markers were in the normal range. Treatment with Octreotide LAR 30 mg/28 days was initiated and gastrin level dropped to 5 x ULN. One year later, another SPECT/CT scan revealed radiotracer accumulation in the gastric antral region and first part of duodenum, associated with increased gastrin level (10 x ULN), which led to the increase of Octreotide LAR to 40 mg/28 days and after 2 months, the gastrin level dropped to 2.4 x ULN. Imaging evaluation showed no metastases. Abdominal surgery was performed, but the primary lesion could not be identified during laparotomy. In the meantime, the patient suffered a severe form of COVID-19 infection with 80% of the lungs being affected. The patient stopped treatment for gastrinoma for almost 2 months and gastrin raised again to 7 x ULN. Morever, the pacient was diagnosed with type 2 diabetes and started treatment with Metformin. Currently, gastrin level is 2.8 x ULN, with mild cholestasis syndrome and normochromic normocytic anemia.

Conclusion: Despite the high gastrin levels, the patient has no metastatatic lesions. One particularity of this case is that even though surgery is thought to be the only curative treatment, the surgical intervention could not find any gastrointestinal tumour. Another particular aspect is the unusual association between RCC and gastrinoma, considering that GRP and its receptor can play an important role in carcinogenesis, this being a future path for novel targeted therapy.

Keywords. gastrinoma, neuroendocrine tumours, carcinoid syndrome, renal cell carcinoma