Lymphoid Neoplasms and COVID-19 Vaccination

It is established that administration of the COVID-19 vaccine may be associated with an exaggerated immune response leading to enlargement of several lymph nodes. Although most cases are benign and self-limiting, some have been reported in the literature as B-cell or T-cell lymphomas, with no reported cases of chronic lymphocytic leukaemia (CLL). We report two cases of follicular lymphoma and CLL that occurred a few weeks after COVID-19 vaccination. Case 1 is a 48-year-old woman who noticed two significantly palpable masses, one in each axilla, 48 h after receiving the first dose of the Pfizer-BioNTech BNT162b2 vaccine for COVID-19. Seven days later, she noticed another mass on the right side of her neck, which was biopsied within 48 hours. Case 2 is a 75-year-old man who presented with localized swellings in the axilla and on the neck, noted 24 h after the first dose of the Moderna messenger RNA-1273 COVID-19 vaccine. Neither patient reported any constitutional or associated symptoms. Surgical biopsy of the axillary lymph node in case 1 revealed a non-Hodgkin lymphoma, confirmed via immunohistochemistry as CD20-positive B-cell follicular lymphoma. The patient also had multiple pre- and para-aortic lymph nodes. In case 2, complete blood count showed lymphocytosis (total white blood cell – 148 × 109/L; lymphocyte differential – 92%), while peripheral blood film showed lymphocytosis with a predominance of small, mature-looking lymphocytes, both suggesting CLL. Although requested, immunophenotyping and molecular testing were not performed due to patient-related challenges. Although a chance occurrence is possible, lymphoid malignancies should be considered a strong differential. The vaccination history of patients presenting with clinical manifestations suggestive of a lymphoid malignancy should be thoroughly investigated, while ruling out other possible differentials such as a benign, self-limiting inflammatory process.