Double‐hit multiple myeloma with atypical “faggot” cells

Abstract

Double-hit multiple myeloma with atypical "faggot" cellsA 60-year-old woman was diagnosed with kappa light chain multiple myeloma following the investigation of proteinuria and deteriorating general health. There was no cytopenia but rare dystrophic plasma cells (2%) with Auer rod-like inclusions in faggots were present in the blood film (images, May-Gr€ unwald-Giemsa, 9100 objective, left). The same morphology was found in a bone marrow aspirate at diagnosis, displaying 38% of myeloma cells (right). Targeted next generation sequencing of sorted plasma cells revealed a bi-allelic inactivation of TP53 (deletion 17p and TP53 mutation) and the presence of a t(11;14)(q13;q32) translocation. Considering this to be ultra high-risk myeloma, intensive treatment is planned.The presence of Auer rod-like inclusions in myeloma cells has been described previously, particularly in patients with kappa light chain myeloma and adverse cytogenetic abnormalities. The unusual feature of faggots of such inclusions should not lead to confusion with other cells, such as atypical lymphoid cells or the abnormal promyelocytes of acute promyelocytic leukaemia. This easily recognised, rare morphological feature is likely to be a marker of aggressive disease.