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Axillary Lymphadenopathy After COVID-19 Vaccination in a Woman With Breast Cancer

Educational Objective
Based on this clinical scenario and the accompanying image, understand how to arrive at a correct diagnosis.
1 Credit CME

A 39-year-old healthy woman without family history of malignancy found a mass in her right breast at 38 weeks of pregnancy. Prior to delivery, she underwent diagnostic ultrasound of the right breast, which showed a possible mass in the location of the palpable lesion that was most consistent with a normal island of fibroglandular tissue. Follow-up mammogram and ultrasound of the right breast (without axillary evaluation) were performed 6 months later, which showed an irregular 17-mm mass with associated pleomorphic calcifications in the same area. Ultrasound-guided biopsy was performed. Pathology showed high-grade, estrogen receptor–positive ductal carcinoma in situ (DCIS). On postbiopsy physical examination, the patient had a palpable 2.5-cm right breast mass at the 3-o’clock position without palpable axillary lymphadenopathy.

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Vaccination-associated reactive lymphadenopathy

D. Perform right axillary ultrasound now, with intent to biopsy enlarged lymph nodes

The keys to the correct diagnosis in this case were the recent receipt of COVID-19 vaccine 1 day prior to MRI, in conjunction with the lack of palpable axillary lymphadenopathy prior to vaccination. This presentation raised suspicion for vaccination-associated reactive lymphadenopathy; however, because of the patient’s recent diagnosis of ipsilateral breast cancer, a targeted axillary ultrasound with intent to biopsy enlarged lymph nodes (choice D) is the best answer. In the setting of newly diagnosed ipsilateral DCIS, the asymmetrically enlarged right axillary lymph nodes identified on MRI could represent an invasive tumor in addition to DCIS with potential axillary lymph node metastasis. Therefore, waiting 4 to 6 weeks (choices A and B) is not recommended. In the setting of DCIS, where less than 25% of patients are found to have invasive carcinoma on final pathology after surgical excision, sentinel lymph node biopsy is performed only in patients for whom the procedure cannot be technically performed as a second operation (eg, mastectomy or those in whom the DCIS excision is in an anatomical location that would compromise the breast lymphatics). For this patient, without a diagnosis of invasive carcinoma and in the setting of a planned medial breast lumpectomy that would not alter the lymphatic pathway to the axilla, sentinel lymph node biopsy (choice C) would not be recommended.

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Article Information

Corresponding Author: Diana L. Lam, MD, Department of Radiology, University of Washington, Seattle Cancer Care Alliance, 1144 Eastlake Ave E, LG2-216, Seattle, WA 98109 (dllam@uw.edu).

Published Online: December 23, 2021. doi:10.1001/jama.2021.20010

Conflict of Interest Disclosures: None reported.

Additional Contributions: We thank the patient for providing permission to share her information.

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AMA CME Accreditation Information

Credit Designation Statement: The American Medical Association designates this Journal-based CME activity activity for a maximum of 1.00  AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Successful completion of this CME activity, which includes participation in the evaluation component, enables the participant to earn up to:

  • 1.00 Medical Knowledge MOC points in the American Board of Internal Medicine's (ABIM) Maintenance of Certification (MOC) program;;
  • 1.00 Self-Assessment points in the American Board of Otolaryngology – Head and Neck Surgery’s (ABOHNS) Continuing Certification program;
  • 1.00 MOC points in the American Board of Pediatrics’ (ABP) Maintenance of Certification (MOC) program;
  • 1.00 Lifelong Learning points in the American Board of Pathology’s (ABPath) Continuing Certification program; and
  • 1.00 CME points in the American Board of Surgery’s (ABS) Continuing Certification program

It is the CME activity provider's responsibility to submit participant completion information to ACCME for the purpose of granting MOC credit.

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