Bone Marrow Involvement of Epstein-Barr Virus-Positive Large B-Cell Lymphoma in a Patient with Angioimmunoblastic T-Cell Lymphoma

Dear Editor, Angioimmunoblastic T-cell lymphoma (AITL) is the second most common subtype of peripheral T-cell lymphoma, accounting for approximately 15–20% of the cases [1]. It is a systemic lymphoproliferative disorder that typically presents with constitutional symptoms, generalized lymphadenopathy, hepatosplenomegaly, skin rash, and immunological disturbances [2]. AITL may be accompanied by either polyclonal or clonal proliferation of B lymphocytes, which seems to be triggered by Epstein-Barr virus (EBV) infection [3]. Although AITL accompanying B-cell proliferation is not rare, the occurrence of large B-cell lymphoma in AITL patients has rarely been reported [2]. Here, we describe bone marrow (BM) involvement of EBV-positive large B-cell lymphoma in a patient who was diagnosed as having AITL. Informed consent was obtained from the patient for this study, and ethical approval was waived by the institutional review board. In December 2016, a 73-year-old man presented with a onemonth history of enlarged cervical lymph nodes, fever, and general weakness. Enlargement of multiple lymph nodes and hepatomegaly were detected by physical examination and computed tomography. A biopsy of the left cervical lymph node (level V) was performed, and the patient was diagnosed as having AITL. Immunohistochemical (IHC) stain results showed small to medium-sized lymphocytes positive for CD3 and CD4 and negative for CD8 and CD20 (Fig. 1). Complete blood count parameters were as follows: hemoglobin, 10.7 g/dL; platelets, 64×10/L; and white blood cells, 18.6× 10/L, with 2% myelocytes, 1% metamyelocytes, 3% band neutrophils, 61% segmented neutrophils, 17% lymphocytes, 4% monocytes, 1% eosinophils, and 11% atypical lymphoid cells (Fig. 2A). BM aspiration failed owing to extensive fibrosis. BM biopsy showed hypercellular BM with about 95% cellularity, which was mostly comprised of large neoplastic lymphoid cells. The neoplastic lymphoid cells were diffusely infiltrated in an interstitial pattern with extensive fibrosis (Fig. 2B). IHC analysis revealed that the large neoplastic lymphoid cells were mostly positive for CD20 but not for CD3, CD4, or CD8 (Fig. 2C and 2D). In situ hybridization for EBV-encoded RNA (EBER) showed nuclear positivity in the large neoplastic B lymphoid cells, although only less than 10% were positive. The final BM diagnosis was BM involvement of large B-cell lymphoma, and the patient was subsequently treated with a CHOP (cyclophosphamide, hydroxyl doxorubicin, vincristine, and prednisone) regimen.