Critical Role of Ga–68 DOTATATE PET-CT in a Patient with Neuroendocrine Tumor and Second Primary Cancer

ABSTRACT

A 70-year-old female with the diagnosis of the metastatic neuroendocrine tumor was referred to our clinic with new abdominal lymph nodes in computed tomography (CT). This finding was considered as the disease progression, and capecitabine along with temozolomide was added to her current lanreotide therapy. The origin of the new lymph nodes was uncertain due to no response to chemotherapy and the stability of the lymph nodes. 68Ga-DOTATATE PET-CT was performed to resolve the inconsistency in clinical and imaging findings. PET-CT images showed high 68Ga-DOTATATE uptake in abdominal, cervical, left supraclavicular lymph nodes, and few metastatic foci in the liver, which were compatible with a neuroendocrine tumor. Additionally, there were bilaterally enlarged lymph nodes in the neck, axillary, intra-abdominal and inguinal area with no tracer uptake. The incongruent findings of PET-CT suggested a biopsy of nonradio-avid lymph nodes for the possible exclusion of other etiologies. Biopsy revealed that the enlargement of the lymph nodes was caused by small lymphocytic lymphoma (SLL) rather than neuroendocrine metastases. 68Ga- DOTATATE PET-CT led to a critical change in the disease management and confirmed the diagnosis of the secondary tumor with the aid of biopsy. A high radiotracer uptake of neuroendocrine metastases on Ga-68 DOTATATE PET-CT suggested to change the chemotherapy (capecitabine+ temozolomide) to Y-90/Lu-177 DOTATATE therapy, which led to disease stabilization and minor regression. Her newly diagnosed stable SLL was followed accordingly. It can be concluded that 68Ga-DOTATATE PET-CT plays a critical role in the management of patients with neuroendocrine tumors and should be used as a problem solving tool in patients with the discrepancy between clinical and imaging findings.