Systemic EBV‐positive T‐cell lymphoma of childhood mimicking anaplastic large cell lymphoma

Abstract

A 24-year-old immunocompetent man was admitted with a 7-day history of high fever, lung nodules, hepatosplenomegaly and multiple enlarged lymph nodes. Laboratory tests showed pancytopenia (haemoglobin concentration 83 g/l, platelet count 69 9 10/l and white blood cell count 3.27 9 10/l) and a high Epstein–Barr virus (EBV) DNA load in peripheral blood (1.42 9 10 copies/ml). The patient had a long history of chronic active EBV infection (CAEBV) presenting with recurrent fever, multiple enlarged lymph nodes and elevated EBV-DNA load. The biopsied samples of lymph node, greater omentum lesion and lung showed either a diffuse or an intravascular pattern of infiltration (top left, greater omentum lesion) with cohesive growth of large atypical cells with irregular nuclei and abundant cytoplasm resembling the hallmark cells of anaplastic large cell lymphoma (top right). The atypical cells were positive for CD3 (bottom left), CD4, CD30, granzyme B, TIA-1 and EBV-encoded small RNA by in situ hybridisation (inset), and negative for CD5, CD8, CD20, CD56 and ALK1 (see Fig S1 for other morphological and immunophenotypic features). Clonal Tcell receptor c gene (TRG) rearrangement supported a T-cell origin (bottom right). A diagnosis of systemic EBV-positive T-cell lymphoma of childhood (STLC) arising from CAEBV was made. The patient underwent intensive chemotherapy, but died of the disease within 2 months of diagnosis. This lymphoma is most often composed of small CD8+ T cells without substantial cytological atypia, while smaller numbers of cases occurring in the setting of CAEBV are CD4 positive. The current rare case, mimicking anaplastic large cell lymphoma, broadens the spectrum of morphological variants of STLC.