Mediastinal plasmocytoma with multiple myeloma: unusual presentation

¹Hematology and Stem Cell Transplant Department, Blood Transfusion and Cellular Therapy, Cheikh Khalifa International University Hospital, Casablanca, Morocco, ²Mohammed VI University of Health Sciences (UM6SS), Casablanca, Morocco, ³Radiology Department, Cheikh Khalifa International University Hospital, Casablanca, Morocco

^&Corresponding author
Nouama Bouanani, Hematology and Stem Cell Transplant Department, Blood Transfusion and Cellular Therapy, Cheikh Khalifa International University Hospital, Casablanca, Morocco

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We report a rare case about a 60 years old Moroccan woman with a past medical history of gastrointestinal tuberculosis, admitted to the emergency department with fever, coughing, weight loss, spontaneous sternum fracture, back and chest pain. A physical examination revealed diffuse bone pain on palpation. Laboratory testing revealed anemia at 9 g/dl, high serum viscosity (80 mm/h). C-reactive protein at 100 mg/l. Serum protein electrophoresis showed monoclonal spike (30g/dL) in the gamma zone. Serum immunofixation study revealed a IgG lambda monoclonal paraprotein. Serum free light chains (kappa/lambda ratio: 0.04). Total protein level (88g/L). Twenty-four hours proteinuria was negative, complete metabolic panel, blood calcium and serum creatinine were normal. Bone marrow aspiration was performed and showed mature and dystrophic plasma cells at 38%. Computerised tomography scan of the chest revealed left broncho-pulmonary focus associated to a sternal fracture (A), mediastinal tissue mass of superior and posterior mediastinum of 30mm diameter (B), scanner-guided biopsy confirmed plasmocytoma, bronchoscopy with biopsy which objectified an inflammatory lesion. Hematological assessment concluded to mediastinal plasmocytoma with multiple myeloma Ig G Lambda. The Revised International Staging System is at 2. The patient received empirical antimicrobial therapy with good response, then she was treated with VTD protocol (bortezomib, thalidomide and dexamethasone), achieving complete remission followed by autologous stem cell transplantation (C,D). Consolidation therapy and maintenance are planned to maintain remission.

Figure 1: A) computerised tomography of the chest: lung window showing left broncho-pulmonary focus; B) computerised tomography of the chest with axial section showing mediastinal tissue mass of superior and posterior mediastinum, of 30mm diameter, adjacent to T2, well limited, homogeneous, without bone lysis, calcifications or necrosis; C) CT chest after treatement: disappearance of lung bronchopulmonary focus; D) computerised tomography of the chest after treatement: disappearance tissue mass of mediastinium