Presentation
Painful lump in the left axilla that developed over the course of a few days.
Patient Data
The lump corresponds to a relatively enlarged lymph node with a short axis diameter of 8 mm. The fatty hilum is compressed by the markedly thickened cortex. Engorged feeding vessels and relative hypervascularity also noted. Otherwise normal status.
Case Discussion
During the course of the exam it was revealed that the patient received the Pfizer-BionTech Covid-19 mRNA vaccine in her left upper arm before developing the lump. Transient lymphadenopathy shortly after administration of mRNA vaccines against Covid-19 has recently been described. Knowledge of this self-limiting, benign effect is important for the coming months, as with population-wide immunization, vaccine-related lymph node enlargement will become an important differential diagnosis of acutely developing axillary lumps 1.