# EBV-Positive Nodal T- and NK-Cell Lymphoma Mimicking Anaplastic Large Cell Lymphoma: A Case Report

## TL;DR

This paper reports a case of EBV-positive lymphoma that resembles another lymphoma type, highlighting the need for accurate diagnosis due to different treatments.

## Contribution

The paper presents a new case of EBV+ NT/NKCL that mimics ALK-negative ALCL, emphasizing diagnostic challenges and clinical implications.

## Key findings

- The lymphoma case showed CD30 positivity and subcapsular distribution, resembling ALK-negative ALCL.
- Lymphoma cells were diffusely positive for EBV, confirming EBV+ NT/NKCL diagnosis.
- Accurate differentiation is crucial due to distinct clinical management requirements between the two lymphoma types.

## Abstract

EBV-positive nodal T- and NK-cell lymphoma (EBV+ NT/NKCL) is a recently recognized entity in the 5th edition of the WHO Classification of Tumors of Hematopoietic and Lymphoid Tissues. Notably, CD30 positivity is frequently observed in (EBV+ NT/NKCL), creating diagnostic challenges to distinguish it from ALK-negative anaplastic large cell lymphoma (ALCL). Furthermore, cases of EBV+ ALCL have been documented in the literature, predating the inclusion of EBV+ nodal cytotoxic T-cell lymphoma as a variant of peripheral T-cell lymphoma. We present a case of a 47-year-old male presenting with multiple lymphadenopathies. The histomorphologic and immunophenotypic features of the lymph node closely resemble ALK-negative ALCL, characterized by uniform CD30 expression and a subcapsular distribution of lymphoma cells. However, the lymphoma cells exhibit diffuse positivity for EBV, consistent with EBV+ NT/NKCL. A case of ALK-negative ALCL with an immunophenotype identical to the EBV-positive case is included for comparison. Given that EBV+ NT/NKCL represents an aggressive neoplasm requiring unique clinical management compared to ALK-negative ALCL, it is critical to accurately differentiate EBV+ NT/NKCL from ALK-negative ALCL with a cytotoxic T-cell immunophenotype.