Castleman disease presenting as DOTATATE-positive retroperitoneal mass

Castleman disease is a rare, heterogeneous group of lymphoproliferative disorders whose imaging characteristics can resemble malignancy. We present a case of a patient who initially presented with intermittent hypertension, palpitations, and chest pain. Despite a negative biochemical workup, CT imaging revealed a left retroperitoneal mass intimately associated with the left adrenal gland with 68Ga-DOTATATE positron emission tomography-computed tomography (PET/CT) detecting uptake in the mass as well as several left para-aortic lymph nodes and bone lesions. Based on the imaging findings, the patient was taken to the operating room for resection of what was presumed to be a metastatic neuroendocrine tumour. However, the diagnosis on histopathological examination was hyaline-vascular Castleman disease. While DOTATATE PET/CT has high sensitivity and specificity for neuroendocrine tumours (NETs), this case report highlights that non-neuroendocrine pathology may result in DOTATATE uptake, and that Castleman disease should be considered when encountering DOTATATE-positive masses on imaging.