Case Series: FDG-avid lymphadenopathy during oncologic staging of pancreatic adenocarcinoma after COVID-19 vaccination

: COVID-19 vaccination is becoming widely available to millions of patients across the world. Lymphadenopathy after recent COVID-19 vaccination is a common side effect that can cause upstaging in oncology patients as it can be misdiagnosed as metastatic disease. This can potentially change treatment and have devastating consequences. We present three cases of FDG-avid lymphadenopathy after recent COVID-19 vaccination in patients undergoing oncologic staging for pancreatic adenocarcinoma. Patient 1 is a 57-year-old female that developed FDG-avid supraclavicular lymphadenopathy after recent COVID-19 vaccination while undergoing pancreatic adenocarcinoma restaging. Excisional biopsy ruled out metastatic disease, and the patient subsequently underwent radiotherapy and surgery. Patients 2 and 3 are a 49-year-old female and 62-year-old male with pancreatic adenocarcinoma undergoing restaging that developed axillary FDG-avid lymphadenopathy after recent vaccination, respectively. The decision was made to observe the lymphadenopathy in both cases as they continued neoadjuvant chemotherapy since they were not metabolically optimized for surgery. Lymphadenopathy in oncology patients after recent COVID-19 vaccination should be managed with a multi-disciplinary team that includes the surgeon, oncologist, primary care provider, and radiologist. Factors such as surgical candidacy, likelihood of reactive lymphadenopathy, probability of metastatic disease, and risk of delaying surgery or treatment should be taken into consideration. Diagnostic imaging and procedures should be avoided if the outcome will not change treatment.