FDG uptake in axillary lymph nodes after vaccination against pandemic (H1N1)

Abstract

This potential pitfall in PET/CT should be borne in mind during current vaccination programmes.

Systemic Immune Response to Vaccination on FDG-PET/CT

“…The highest uptake typically occurred within the first 2 weeks after vaccination [1,3], but persisted beyond 1 month in some cases [2]. Additionally, lymph node size was normal [1][2][3][4], in contrast to our case. These reports advocate caution when considering changes to the treatment plan prior to confirmation of the suspected false-positive uptake.…”

“…Several previous reports demonstrated the occurrence of false-positive ipsilateral FDGavid axillary lymph nodes following vaccination [1][2][3][4]. The highest uptake typically occurred within the first 2 weeks after vaccination [1,3], but persisted beyond 1 month in some cases [2]. Additionally, lymph node size was normal [1][2][3][4], in contrast to our case.…”

“…Compared to the initial scan (left), new enlarged and FDG-avid left axillary lymph nodes (a) were seen on the examination 2-3 days following the influenza vaccination (middle), which resolved 12 days later (right). Several previous reports demonstrated the occurrence of false-positive ipsilateral FDGavid axillary lymph nodes following vaccination [1][2][3][4]. The highest uptake typically occurred within the first 2 weeks after vaccination [1,3], but persisted beyond 1 month in some cases [2].…”

Nano‐particle vaccination combined with TLR‐7 and ‐9 ligands triggers memory and effector CD8+T‐cell responses in melanoma patients

“…This has not been utilized in vaccine studies so far. It has rather been described as an epiphenomenon in relation to the last vaccination campaigns against influenza A/H1N1 pandemic as seen in patients undergoing oncologic PET/CT [40][41][42] or in sporadic immunization cases [43,44]. Increased glucose metabolism in lymph nodes was not observable >14 days after immunization in the study by Burger et al [42] or >30-50 days by Thomassen et al [41], possibly due to the shorter stimulation time of these vaccines as opposed to the vaccine formulations used in the present study.…”

New axillary lymph nodal F-18 fluoro-deoxy glucose uptake in an interim positron emission tomography scan - not always a sign of disease progression

“…[6] One study by Karam, et al ,[7] also reported that around 50% of bilateral hilar lymph nodal FDG uptake in patients with lymphoma is due to inflammatory/granumatous pathology. Apart from this potential limitation of non-specific uptake false-positive FDG uptake has also been reported in axillary lymph nodes following immunization,[89] infectious/inflammatory pathologies[10] and rarely due to injection extravasation. Axillary lymph nodal FDG uptake in case of extravasation is related to lymphatic drainage from soft tissues of upper limb into axillary lymph nodes from the site of extravasation.…”