Radiological Characteristics of Immunization Adenitis in the Axilla Following the Covid-19 Vaccine

Abstract

It was aimed to investigate the ultrasonography (US) features of axillary COVID-19 immunization adenitis. Patients with axillary COVID-19 immunization adenitis detected between April 2021 and January 2022 were included. US features of the lymph nodes identified at the patient's initial US were all recorded. Radiological follow-up information and if exists pathology results were investigated. 104 immunization adenitis in the axilla following Covid-19 vaccine were detected. Only 18.3 percent had axillary pain or edema. Biopsy was recommended for 4 patients and follow-up was recommended for the other 100 patients. Core biopsy results were lymphoid tissue with focal micro-abscess formations, reactive lymphoid hyperplasia and plasma cell increase. All of the patients had a history of vaccination in the last 3 months. After immunization, initial US imaging was conducted mean 24-days later. The mean long and short axis were 22-mm and 13-mm, respectively. The mean long-short axes ratio was 2.2. The mean thickness of the cortex was 4.8-mm. The long and short axes of the lymph nodes in the first US and control examinations were compared statistically and they decreased in time. The hilum existed (96%). Elastography revealed soft features. The majority of the immunization adenitis are just enlarged benign-appearing lymph nodes. The majority were found during the extensive immunization campaign and were asymptomatic. Patients and their physicians should be aware of the vaccination and imaging evaluation of specific patient groups considering that these vaccinations will continue to be used for a while in the next years.