Vancomycin-Induced Maturation Arrest with Reactive Promyelocyte Proliferation: A Diagnostic and Therapeutic Challenge.

Drug-induced leukopenia is a diagnostic and therapeutic challenge. A detailed clinical history is a must to come to a right diagnosis. Certain drugs are known to cause bone marrow suppression, leukopenia, myeloid maturation arrest, and reactive promyelocyte proliferation. Here, we report an unusual case of vancomycin-induced maturation arrest with marked promyelocyte proliferation in a 47-year-old male patient who was being treated for novel coronavirus disease 2019 (COVID-19) infection. Most times, this reactive promyelocyte proliferation is confused with neoplastic promyelocytes, leading to incorrect diagnosis and management.