Sonography of subcutaneous nodules following immunization with histopathological correlation: a three-case series

Subcutaneous nodules are a rare adverse event following immunization frequently associated with suboptimal injection procedures and aluminium-containing vaccines. We present three cases of subcutaneous nodules following immunization describing their clinical signs, histopathological features and ultrasound findings and demonstrating the use of sonography as an aid to the diagnosis of this entity.