Intravascular large B-cell lymphoma with bone marrow involvement at presentation and haemophagocytic syndrome: two Western cases in favour of a specific variant

Aims: To report two cases of an unusual form of intravascular lymphoma, cha racterized by bone marrow involvement at presentation with haemophagocytic syndrome, Methods and results: We describe the clinicopathological features of two pa tients with intravascular lymphoma primarily involving bone marrow, Both pa tients complained only of fever with pancytopenia and reactive haemophagocy tic syndrome, Diagnosis was made on bone marrow examination, which showed l arge tumour cells of B-cell lineage confined within the lumen of sinuses. Conclusion: These two cases and five previous reports could represent a var iant of intravascular lymphoma, characterized by early involvement of bone marrow without dissemination to other organs. This form of intravascular ly mphoma, called IVL-HS, seems to be an 'Asian' variant with a high prevalenc e in Asian people and a very low prevalence in Western countries. At a prac tical level, bone marrow biopsy may be useful in the diagnosis of intravasc ular lymphoma when the clinical presentation is restricted to fever of unkn own origin with a reactive haemophagocytic syndrome.