Abnormal Chromatin Clumping in Myeloblasts Mimicking Chronic Lymphocytic Leukaemia: A Diagnostic Pitfall

Abnormal chromatin clumping (ACC) in cells of myeloid lineage is a distinct morphological entity. It has been described mainly in polymorphs in haematological neoplasms involving myelodysplasia or myeloproliferation. We here describe a rare case of ACC in myeloblasts in an elderly man that mimicked chronic lymphocytic leukaemia. Flow cytometry played a crucial role in characterizing the myeloid lineage of the blasts, thus avoiding a misdiagnosis. To the best of our knowledge, this is the third time such a case has been reported in the literature.