A 57-year-old man, with a personal history of COPD, smoker of 15 packs/year and moderate drinker, consulted for a fast-growing, painless tumour, firmly adherent to deep planes, of one month's evolution, in the region of the sternal manubrium. Plain X-ray and CT scan with intravenous contrast and three-dimensional reconstruction of the thorax showed a tumour measuring 5-6 cm in diameter in the sternal manubrium with cortical destruction. There were no signs of mediastinal infiltration or infiltration of the clavicles. (See Figures 1 and 2).

General laboratory tests showed no significant alterations, with normal immunoglobulin studies (IgG, IgA, IgM and beta 2 microglobulin).
A FNA was performed and a surgical biopsy was performed, finding an atypical cytology that was not conclusive of the histological type. Immunohistochemistry tests were positive for the following markers: CD 138; CD 68 (isolated); LAMBDA (some cells); KAPPA (intense positivity in almost all cells). Plasmacytoma was suspected. Bone scintigraphy only showed increased uptake in the region of the sternal tumour and both sternoclavicular joints. Bone marrow biopsy showed no pathological findings and urine examination revealed the absence of Bence-Jones proteins.
Wide en bloc removal of the sternal manubrium and partial resection of both clavicles, the first two ribs and the body of the sternum, including the skin overlying the tumour, were performed. No mediastinal infiltration was observed. Coverage of the resulting defect with a polypropylene mesh and suture of the pectorals in the midline. There were no postoperative complications. The fixation and stability of the chest wall were satisfactory from the immediate postoperative period. Hospital stay was 7 days. The anatomopathological description of the operative specimen indicated abundant mononucleated plasma cells intermixed with multinucleated ones with immunohistochemical positivity for antiCD138 and lambda chain antibodies and negativity for kappa chain antibodies. The resection margins were free of disease. Treatment was completed with radiotherapy (50 Gy in 30 sessions over 4 weeks).
At the 6-month postoperative follow-up, no clinical or tomographic signs of disease progression or late postoperative complications were evident.