Role of Immunohistochemistry in Acute Leukemias with Myelonecrosis.

Myelonecrosisis a rare antemortem finding most commonly seen in haematopoeitic neoplasms, especially in acute leukemia. When myelonecrosis occurs at the time of presentation, it imposes certain diagnostic issues in sub categorization of leukemias which is necessary for therapeutic as well as prognostic purposes. Flow cytometry, though is a powerful modality, has its own limitations especially when the cells are not fresh and viable; and when the specimen is not of adequate cellularity which is usual in cases of myelonecrosis. In such situations, immunocytochemistry (ICC) or immunohistochemistry (IHC) may play a major role in lineage specification in leukemias as the necrosed marrow with the ghost cells can still retain the antigenicity for certain immunomarkers. Four such interesting cases of common B acute lymphoblastic leukemia (ALL) where IHC was used for diagnosis were included. ICC and IHC done on the necrosed marrow contributed to the diagnosis of ALL in all the four cases and contributed to subsequent management. ICC and IHC if contributory can play a major role in identifying the primary cause of myelonecrosis as the ghost cells can retain the antigenicity despite being morphologically non-viable.