Spectrum of bone marrow findings in patients with angioimmunoblastic T-cell lymphoma.

Bone marrow (BM) biopsy is often performed early in the evaluation of patients with angioimmunoblastic T-cell lymphoma (AITL), and may be the first diagnostic tissue sample; yet the BM histopathology associated with this disease has not been well described. In this study, BM specimens from 13 patients with AITL were reviewed. Seven (54%) were involved by AITL, which was characterised by paratrabecular and interstitial polymorphous infiltrates containing cytologically atypical lymphocytes, histiocytes and eosinophils. The neoplastic cells were positive for CD10 and CXCL13 by immunohistochemistry in a subset of cases. As in lymph nodes, the lymphomatous infiltrate in some BMs contained numerous small or scattered large B cells, resembling either benign lymphoid aggregates or T cell rich large B cell lymphoma, respectively. Secondary haematological changes were frequent and presented independent of BM involvement by AITL; these included trilineage haematopoietic hyperplasia and plasmacytosis. When BM biopsy preceded the diagnosis of AITL, these secondary changes were misinterpreted as chronic myeloproliferative disease (n = 2), or plasma cell dyscrasia (n = 2). In two cases, these changes obscured the presence of BM involvement by AITL. The spectrum of BM findings in AITL patients is important to recognise for early and accurate diagnosis in this disease.