Auer rod-like inclusions in the cytoplasm of B-cell lymphoma cells with bone marrow infiltration.

Auer rod-like inclusions are rarely seen in B-cell neoplasms patients. Here, we present a case of B-cell lymphoma with Auer rod-like inclusions in lymphoma cells. By light and transmission electron microscopy, these structures closely resembled Auer rods which were found in acute myeloid leukemia. The Auer rod-like inclusions were negative for cytochemical staining of MPO, α-naphthyl acetate esterase, and periodic acid-Schiff. Immunostaining and flow cytometric analysis confirmed monoclonal Kappa-positive malignant lymphocytes. Interestingly, the Auer rod-like inclusions exhibited diverse ultrastructural features, which ranged from fusiform, to needle-shape, to round, to crystalline cuboid, to long rod, to short rod and others; some were membrane structures, some membrane-free dense structures, and some lamellar structures. The patient was diagnosed with B-cell lymphoma with bone marrow infiltration.
(Copyright © 2019. Published by Elsevier Inc.)