Lambda light chain multiple myeloma presenting as pleural mass

Light chain multiple myeloma occurs in 20% of multiple myeloma cases. Extramedullary dissemination of multiple myeloma is rare and involvement of pleura by it is even more rare. A 40 years old female patient presented with complains of recurrent vomiting for last 2 months and cough with expectoration for last 1 week. Chest X-Ray (PA view) showed a rounded homogenous opacity in mid zone of left lung field. CECT (thorax) showed pleura based soft tissue density mass lesions overlying apicoposterior segment of left upper lobe and lingular lobe with lytic destruction of underlying 2nd rib. Ultrasound scan of abdomen was normal. CT guided FNAC from soft tissue mass lesion of left side revealed atypical plasma cells, some of them were binucleate and few appear pleomorphic. Bone marrow aspiration showed 20% atypical plasma cells. Serum protein electrophoresis revealed a thin discrete band in gamma globulin region, while serum immunofixation electrophoresis showed presence of lambda light chain band only, with absence of kappa band, IgG band, IgM band and IgA band. Patient was diagnosed as a case of lambda light chain multiple myeloma with extramedullary dissemination to pleura presenting as pleural mass.