Background: The patient was a 65-year-old White woman who presented to dermatology with a painless, rapidly growing exophytic nodule on her left upper cheek.
Aims/purpose: In this case report, we aim to demonstrate the difficulty of diagnosing Epstein-Barr virus-negative extranodal NK cell lymphomas given the broad differential of NK cell lymphomas and the rarity of EBV-negative extranodal NK cell lymphoma.
Methods: Immunohistochemical studies confirmed the diagnosis of cutaneous, extranodal NK cell lymphoma. Interestingly, Epstein-Barr virus in situ hybridization was negative, which is unusual for most NK cell lymphomas.
Results/conclusions: In our view, a combination of immunohistochemistry, clonality assessment, sequencing, and flow cytometric studies is required.
Keywords: Differential diagnosis; Epstein–Barr virus; Extranodal NK/T cell lymphoma; Immunohistochemistry; Lymphoproliferative disorders/diagnosis.
© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.