Recurrent Plasma Cell Myeloma with Intracytoplasmic Auer Rod-like Inclusions after Autologous Hematopoietic Stem Cells Transplantation

Abstract Introduction/Objective Plasma cell myeloma (PCM) is a bone marrow based neoplastic disorder of plasma cells (PCs). The detection of intracytoplasmic Auer rod-like inclusions (ARLI) is rare in PCM. The correlation between the ARLI and the diagnosis, recurrence, prognosis of PCM remains unknown. Methods/Case Report Retrospective comparison of pathological findings between two separate bone marrow biopsies of a recurrent kappa-restricted, IgA-positive PCM with intracytoplasmic ARLI before and after autologous hematopoietic stem cell transplantation (HSCT) with a 7-year observation. A detailed review of all the published cases of PCM with intracytoplasmic ARLI. Results (if a Case Study enter NA) The neoplastic PCs exhibited anaplastic features in the original diagnosis but became relatively mature in the recurrence after the autologous HSCT. The intracytoplasmic ARLI were found in both cases and tended to increase in the recurrence. The patient’s renal function was within normal range at the first diagnosis and during the recurrence. To the best of our knowledge, about 41 cases have been published since the first description of ARLI in 1940 including 16 females (age of onset: 38 to 72 years, mean: 57.7 y), and 25 males (age of onset: 34 to 79 years, mean: 58.2 y). The lysosomal origin of ARLI with the predominance in kappa-restricted, IgG- producing PCM and possible correlation with adult Fanconi syndrome were described. Only 7 kappa-restricted, IgA- producing PCM with ARLI were among them. Conclusion Our case is the first recurrent kappa-restricted IgA PCM with ARLI after autologous HSCT. The morphologies of the neoplastic PCs have changed from anaplastic to relatively mature and more have ARLI in the recurrence. However, the correlation with the adult Fanconi syndrome is not observed in our case. The average age at diagnosis is similar between male and female and might be younger than the average age (69 years) at diagnosis for all PCM.