Endocrine Abstracts

Background

It has been well recognized that grade heterogenity exists within well-differentiated neuroendocrine tumors (WD-NETs). Targeted therapy plays an important role in metastatic disease control.

Case presentation

We present the case of a 58-year-old male patient who was diagnosed with a pulmonary tumor on computer tomography (CT) and underwent a posterobasal left lobectomy. On immunohistochemical staining, synaptophysin and chromogranin A were positive, and the Ki-67 index was 10%, thus the tumor was graded as G2. Treatment with interferon alfa was administered for 7 months, followed by somatostatin analogues (Octreotide). Tumor markers increased suddenly withing a year from diagnosis. Bone scintigraphy identified multiple hypermetabolic lesions, also confirmed on 18F-FDG PET CT and Ga68-DOTATOC PET CT, along with hepatic and splenic high-uptake lesions. Octreotide dose was increased from 30 mg to 60 mg every 28 days. The patient also underwent at this point 2 peptide receptor radionuclide therapy (PRRT) sessions with Lu-177-DOTATATE but at reevaluation with Ga68-DOTATOC PET CT, multiple liver metastasis, with no SSR expression appeared. Percutaneous liver biopsy of the avid nodules showed tumor cells similar to the primary tumor, with a Ki 67% index of 12%. Treatment with Everolimus was initiated in order to decrease hepatic tumor burden, but it produced mild to moderate adverse effects (e.g. rash, fever), which in the end led to dose reduction. During reassessment, the CT scan showed slight progression of the liver metastasis and the tumor markers increased due to tumor necrosis.

Conclusion

Prognostic parameters should be established for WD-NET in order to prevent progression of the disease. Furthermore, in cases of progressive disease, different anti-tumor agents are necessary in order to ensure progression-free survival.