Delayed and Long-Lasting Response to 177Lu-DOTATATE in a Head and Neck Paraganglioma: Case Report and Literature Review.

Introduction: Malignant paragangliomas (M-PGL) are a group of neuroendocrine tumors that originate from chromaffin cells. The most common location for PGL is the head and neck, which comprise 65-70% of all PGL, and the M-PGL accounts for 0.6% of all head and neck cancers. It is a rare tumor, with an incidence of 2-8 per million. Diagnosing PGL can be challenging, and treatment for metastatic disease is usually not curative. Case Presentation: A 66-year-old woman was diagnosed with left cervical pain and laterocervical mass in March 2015. Octreotide scintigraphy showed intense uptake in the cervical mass, two pulmonary micronodules of 4-5 mm, and another lesion in the lumbar region (L3-L4). The final diagnosis was malignant nonsecretory PGL with adjacent tissue involvement and distant metastases. After three different treatments with minimal symptomatic improvement, 177Lu-DOTATATE was requested off-label. With a dose of 7,400 MBq until January 2018, the patient showed remarkable symptomatic pain improvement and a decrease in tumor size. Conclusion: We believe that our case report provides relevant information that can be considered in similar cases. First, the patient tripled the expected survival in such a clinical setting, and this benefit seems to rely on 177Lu-DOTATATE treatment. Second, we documented an early symptomatic response to this treatment but a long-term delayed volumetric radiographic response.