Year: 2024
Type: article
Abstract: We read with great interest the report published by Craig et al,1 as well as corresponding letters.2,3 We would like to share a case with the readership to emphasize that COVID-19 vaccine-associated Kikuchi-Fujimoto disease (KFD) can mimic non-Hodgkin lymphoma, especially when sampled by core needle biopsy. The patient was a 45-year-old woman who received COVID-19 messenger RNA vaccines in early 2021—she had associated fever and lymphadenopathy, which resolved. Three months later, she underwent screening mammogram that revealed a 1.4-cm right axillary lymph node with thickened capsule. Her physical examination was unremarkable, and complete blood count, lactate dehydrogenase, hepatitis B, and HIV serologies were within normal ranges. The patient underwent computed tomography (CT)–guided core needle biopsy, reviewed by a hematopathologist. H&E-stained sections showed an atypical lymphoid infiltrate characterized by an immunoblastic proliferation of T cells associated with karyorrhectic debris and crescent-shaped histiocytes. The T cells expressed CD2 and CD7, with decreased CD5—they mostly lacked CD4, CD8, and CD30. Ki-67 highlighted 60% to 70% of nuclei. A second opinion by a consulting hematopathologist favored peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS). T-cell receptor (TCR) gene rearrangement testing could not be performed due to scant material. Whole-body positron emission tomography–CT showed mildly fluorodeoxyglucose-avid right axillary, paratracheal, and para-aortic lymph nodes. A staging bone marrow biopsy specimen was negative. The patient underwent excisional biopsy 17 days after the core biopsy—the histology showed changes with the prior biopsy specimen and follicular hyperplasia but no lymphoma or overt histology supporting KFD. By immunohistochemistry, CD20 showed B cells in well-formed follicles, and CD3 showed a normal distribution of small T cells. There was no loss of CD5 on the T cells, and CD30 highlighted scattered immunoblasts. Flow cytometry and TCR gene rearrangement studies were not performed. The referring hematologist recommended chemotherapy for PTCL-NOS. The patient received 1 cycle of brentuximab vedotin with cyclophosphamide, hydroxydaunorubicin, and prednisone, which she tolerated poorly. Subsequently, she sought a second opinion at our institution. As part of continuity of care, the patient’s pathology cases were reviewed by our hematopathology team. The atypical proliferation of T cells was noted, but based on the associated necrosis, karyorrhexis, and crescent-shaped histiocytes, a diagnosis of KFD was favored. The core biopsy specimen was sent externally to a fourth hematopathologist, who rendered a diagnosis of “atypical T-cell proliferation” and suggested the possibility of KFD, noting that T-cell lymphoma could not be ruled out entirely. On the basis of these data, the hematologists at our institution revised the patient’s diagnosis to COVID-19 vaccine-associated KFD and recommended observation. A follow-up CT scan 6 weeks after the initial biopsy showed resolution of adenopathy. The patient is asymptomatic 2.5 years after her initial biopsy. Kikuchi-Fujimoto disease is among one of the most common histopathologic findings of lymph nodes following COVID-19 vaccination, and it often shows an exuberant T cell–mediated immune response.1,4 These activated T cells can demonstrate an aberrant phenotype with the loss of 1 or more T-cell antigens.5 This case clearly demonstrates the clinical and pathologic diagnostic challenges in differentiating KFD from T-cell lymphoma. In sum, we emphasize the following: (1) the histology and immunophenotype of KFD, especially on a small core needle biopsy specimen, can have overlapping features with T-cell lymphoma and can cause diagnostic dilemmas, and (2) clinical history and extent of involvement are useful when distinguishing KFD from T-cell lymphoma.
DOI: 10.1093/ajcp/aqae016
Institution: University of Minnesota
Language: English
Subfield: Surgery
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4392618910