Metastatic Malignant Paraganglioma of Rare Sites Failed on Conventional Treatments Demonstrating Beneficial Response to 177 Lu-DOTATATE PRRT.

The incidence of paraganglioma (PGL) is rising due to better imaging modalities employed for evaluating incidentaloma and surveillance of the asymptomatic carriers. Benign and malignant PGLs often cannot be reliably diagnosed on histology alone, and the documentation of metastases is important in the diagnosis of malignancy. Advancement in genomics has improved our understanding of PGL. 68 Ga-DOTATATE positron emission tomography (PET)/computed tomography (CT) scan shows a significant superior detection rate compared with other conventional functional and anatomical imaging modalities, can detect rare sites of primary disease in PGL, and also aids in patient selection for peptide receptor radionuclide therapy (PRRT). PRRT is increasingly used in metastatic setting with good symptomatic and biochemical response and disease stabilization in metastatic PGL patients. We present a series of three patients with PGLs located in rare primary sites (sigmoid colon, urinary bladder, and carotid body space), which showed recurrence of disease on conventional treatments and developed metastatic disease in the lymph nodes, liver, skeleton, and lungs. PRRT with 177 Lu-DOTATATE achieved symptom control, favorable biochemical and imaging responses, and increased progression-free and overall survival rate in the described patients.