COVID-19 vaccine-related axillary edema in breast imaging setting.

Worldwide, many vaccines have been developed in response to the COVID-19 pandemic. Unilateral reactive axillary adenopathy related to the COVID-19 vaccine is a well-known occurrence. In addition, axillary edema has also been observed following COVID-19 vaccinations in patients undergoing breast MRI, and radiologists need to be aware of this possibility to avoid performing unnecessary work-up that can be costly to the health care system and be stressful for patients.

Introduction

Although unilateral axillary adenopathy has been well-recognized after administration of the COVID-19 vaccine and its management has been previously discussed and recently reviewed with a polled data [1], a new phenomenon has emerged, specifically as an imaging finding in women undergoing breast MRI. It refers to an acute axillary edema, which can be seen alone or in association with lymphadenopathy. This article aims to discuss 2 high-risk patients with histories of recent ipsilateral upper extremity COVID-19 vaccination who presented with imaging detected ipsilateral unilateral axillary edema with associated adenopathy.

Case 1

A 55-year-old high-risk woman with a family history of breast cancer and a lifetime risk of breast cancer estimated at 28% presented for a screening breast MRI. The patient had received the second dose of the Pfizer-BioNTech vaccine in the left upper arm 3 days before the MRI. On MRI, the breasts had minimal background enhancement and were unremarkable; in the left axilla, lymphadenopathy with associated edema was detected. The patient was recalled for further evaluation of her left axilla. On a subsequent ultrasound., 6 days after the vaccination, a prominent lymph node was identified, without associated edema (Fig. 1).

Fig. 1

Axial T1-weighted sequence without fat saturation (A) and fat saturated, contrast enhanced MRI image (B) shows prominent left axillary lymph nodes with thickened cortex and absence of the fat in the hilum at level I (arrow). Bilateral T2-weighted short tau inversion recovery (STIR) reconstructed coronal (C) and axial (D) MRI demonstrate hyperintense T2 signal in the left axilla asymmetric compared to the right axilla, compatible with edema (arrow). Left axillary grayscale ultrasound, transverse plane (E,F) shows lymph node with thickened cortex, which underwent FNA (single arrow – lymph node; double arrow - needle). Magnified image of Pap-stained ThinPrep slide (G) showing polymorphous lymphoid population with follicular germinal center fragments. Magnified image of H&E-stained paraffin block (H) showing multiple fragments of benign lymphoid tissue with no evidence of metastatic carcinoma.

Case 2

A 52-year old high-risk woman, a BRCA2 gene mutation carrier, presented for screening breast MRI. The patient had received the second dose of the Pfizer-BioNTech vaccine in the left upper arm 2 days before the MRI. On MRI, lymphadenopathy with associated edema was detected in the left axilla. On the left axillary ultrasound, 5 days after vaccination, a slightly enlarged reactive lymph node with mild cortical thickening was seen without associated edema (Fig. 2).

Fig. 2

Axial T1-weighted sequence without fat saturation (A) and fat saturated, contrast enhanced MRI image (B) show a left axillary lymph node with lack of fat in the hilum, at level I (arrow). Bilateral T2-weighted short tau inversion recovery (STIR) MRI reconstructed axial (C) demonstrate hyperintense T2 signal in the left axilla asymmetric compared to the right axilla, compatible with edema. Bilateral axillary grayscale ultrasound, transverse plane (D,E) shows left-sided lymph node with thickened cortex but no edema is identified (D), which underwent FNA (single arrow – lymph node; double arrow - needle) (E). Magnified image of Pap-stained ThinPrep slide (F) showing polymorphous lymphoid population with follicular germinal center fragments.

Discussion

Lymphadenopathy in the axillary and the neck regions is known to be related to COVID-19 vaccine injections as part of the immunological response [2]. This has been documented in the literature as occurring shortly after receiving a vaccine that elicits a strong immune reaction, such as Bacille Calmette-Guerin, smallpox, human papillomavirus, or H1N1 influenza [3], [4], [5], [6], and has been well described after the first and the second doses of 3 types of COVID-19 vaccines, including Pfizer-BioNTech, Moderna, and Oxford-AstraZeneca, commonly occurring within 2-4 days after vaccination with a median duration of 12 days and 5 days after the first and the second vaccinations, respectively [1]. Although the incidence of vaccine-induced axillary lymphadenopathy appears to vary according to patient's age and vaccine's type, axillary lymphadenopathy has been reported in 7% of patients aged 12-15 years and up to 64% in patients over 55 years with Pfizer -BioNTech (BNT162b2), and overall up to 1.1% with Modern (mRNA-1273) vaccine [7], [8], [9]. The true rate of vaccine-associated axillary lymphadenopathy may be higher than reported because axillary symptoms were registered as an incidental side effect, which may cause underestimation. However, as far as we know, there is only one case report describing COVID-19-related acute axillary edema as part of the immune reaction [10]. In line with what was previously reported [10], this phenomenon seems to be acute, self-limited, as it was imperceptible on subsequent ultrasound a few days after the vaccination. As the administration of COVID-19 vaccine has become widespread, it is important to recognize this acute vaccine-related reaction. In addition, a delay in scheduling screening MRI studies may be prudent to avoid identifying this phenomenon and to prevent any unnecessary work-ups.

Patient consent

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