Primary plasma cell leukaemia with multiple extramedullary involvement

Abstract

A 51-year-old man presented with left facial swelling and a gingival mass originating from left maxilla. He developed progressive right proptosis with visual loss and subsequently passed melena. Laboratory tests showed leucocytosis (27.8×10 9 /L) with 32% circulating plasmablasts (8.9×10 9 /L), anaemia (Hb 95 g/L), acute kidney injury (creatinine 149 mmol/L), hypercalcaemia (2.86 mmol/L) and IgG-lambda paraproteinaemia (40 g/L). Flow cytometry confirmed lambda light chain restriction of the plasmablasts (CD138 + CD10 − CD56 + ). CT scan identified soft tissue masses in left maxillary antrum and right orbit with optic nerve compression. Oesophago-gastroduodenoscopy found multiple ulcerated nodules in stomach. Gingival and gastric biopsies showed high-grade haematolymphoid malignancy with plasmacytic differentiation. Bone marrow examination revealed infiltration by sheets of plasmablasts which were negative for EBER. Anti-HIV serology was negative. Cytogenetic study reported a complex karyotype while FISH demonstrated gain of CKS1B and deletion of TP53. These findings are consistent with primary plasma cell leukaemia (PCL). The patient achieved very good partial response with VTD-PACE chemotherapy and was intended for autologous haematopoietic stem cell transplantation. However, he developed frank relapse before stem cell harvest and eventually succumbed despite salvage therapy. This case highlights the highly variable manifestation of PCL and underscores the importance of multidisciplinary inputs towards prompt and accurate diagnosis.