Case Summary

A 69 year old female presented with recurrent chest infections along with progressive neutropenia and anaemia. Bone marrow evaluation demonstrated an extensive B lymphocyte infiltrate in addition to increased plasma cells totalling 80% and 10-20% of respective cellularity on trephine biopsy.

Based on further immunohistochemical, cytogenetic and molecular profiling in conjunction with clinical features, both BRAF mutated hairy cell leukaemia and IgG kappa multiple myeloma were confirmed. Abundant lytic lesions throughout her axial skeleton as well as an hypermetabolic spleen were present on positron emission tomography and computed tomography.

Due to a greater marrow burden of hairy cell leukaemia as well as her degree of anaemia, treatment with cladribine and rituximab was first administered which resulted in normalisation of her cytopenias. Bortezomib, lenalidomide and dexamethasone is now planned to address her multiple myeloma. Careful consideration is being given to the role of melphalan autologous stem cell transplantation in light of acquired DNMT3A and TET2 mutations, detected within the bone marrow, which may heighten her risk of therapy-related myeloid neoplasms in future.