A 73-year-old man presented with lymphadenopathy, hepatosplenomegaly, and a variety of hematological and immunological abnormalities. The bone marrow was replaced by polymorphic cellular infiltrates containing aggregates of CD10(+) T-cells. Circulating lymphoplasmacytic/immunoblastic cells showed an early plasma cell immunophenotype on flow cytometric analysis. Combination of these observations indicated that the underlying disorder of this patient was angioimmunoblastic T-cell lymphoma (AITL); postmortem pathology was consistent with progression of peripheral T-cell lymphoma. Even in the absence of definitive lymph node biopsy, the appearance of the bone marrow and the peripheral blood can lead to the diagnosis of AITL.