The incidence rate of tuberculosis in developed countries is low. The most common presentation of this disease is its pulmonary form but with the increasing use of immunosuppressive drugs, extra-pulmonary tuberculosis is re-emerging. Nevertheless, sternal bone involvement is uncommon. We report the case of an eighty-three-year-old man who presented a painful sternal mass which progressed towards cutaneous ulceration. The first diagnostic hypothesis was neoplasia. The pathological and microbiological diagnosis of tuberculosis was achieved after surgical biopsy. The patient received treatment against tuberculosis for nine months enabling recovery without surgery. This case illustrates the importance of having a diagnosis prior to any kind of treatment facing any voluminous parietal thoracic lesions. This diagnosis is made possible by surgical samples and interdisciplinary teamwork. This case underlines that tuberculosis remains a differential diagnosis that must be evoked in case of unusual bone mass.