Primary bone marrow T-cell/histiocyte-rich large B-cell lymphoma: a diagnostic challenge

We report a primary bone marrow diffuse large B-cell lymphoma in a 52-year-old post-menopausal woman that evaded definitive diagnosis initially due to deceptive clinical features, non-contributory radiological findings, and an extensive reactive lymphoid infiltrate masking the relatively few neoplastic B-cells on bone marrow biopsy. The correct diagnosis was apparent only after a repeat bone marrow procedure and review of the previous histology and immunohistochemistry. The case illustrates the pitfall of assuming mixed B- and T-cell infiltrates in the bone marrow to be invariably benign. A high index of suspicion regardless of the clinical and/or radiological absence of lymphadenopathy or organomegaly and critical examination of each individual cell population in immunohistochemically stained material are essential for correct identification of this rare entity.