Bone marrow trephine immunohistochemistry is useful in characterizing malignancy-associated myelonecrosis: A retrospective observational study.

Objective: We aim to describe the utility of immunohistochemistry (IHC) in characterizing malignancy-associated myelonecrosis (MN) on bone marrow trephine biopsies (BMBx) as a part of initial workup.

Materials And Methods: Patten and intensity of antigenic immunoexpression in necrotic tumor cells on BMBx were evaluated in a series of cases using standardized avidin-biotin-complex immunoperoxidase technique after heat-induced epitope retrieval and compared the same with viable tumor cells wherever available.

Results: Fifteen out of 2494 (0.6%) cases (median age: 28 years; range: 4 to 66 years) had evidence of MN (extensive in eight, moderate in five, and focal in two) secondary to hematological (N = 9) and solid (N = 6) malignancies. Five (33.3%) had pancytopenia, and eight (53.3%) had difficult and/or hemodiluted aspirate. Antigenic expression for CD10, CD79a, CD3, CD7, and CD20 was retained by necrotic leukemic blasts or lymphoma cells; CD34, TdT, and PAX5 showed heterogeneous expression; and a weak Golgi zone (dot like) CD30 positivity was noted in Reed-Sternberg (RS) or RS-like giant cells. Necrotic epithelial metastases retained pancytokeratin in all and showed variable positivity for prostate-specific antigen, carcinoembryonic antigen, CK20, ER, PR, and GATA3. Necrotic neuroblastomas (N = 2) retained positivity for synaptophysin and chromogranin, whereas retained nuclear positivity for NKX2.2 in necrotic Ewing family of tumor (N = 1) aided in early diagnosis.

Conclusion: Myelonecrosis may retain tumor antigenicity, and immunohistochemistry using selected panel of antibodies should be tried in such challenging cases for an early presumptive diagnosis and further decision making.