Giant-cell anaplastic carcinoma with osteoclastic giant cells of the chest cavity: a distinctive form of thymic carcinoma?

Here, the authors describe a case of giant-cell anaplastic carcinoma with osteoclastic giant cells of the chest cavity-which could be a distinctive form of thymic carcinoma-which expressed CD5 and CD45. To the authors' knowledge, there has been no previous report on this subject. A 62-year-old woman presented with continuous pain in the left back associated with coughing and shortness of breath for more than 2 months prior to referral to the hospital. Palliative resection of a mediastinal tumor was performed. During the operation, it was found that the mass occupied most of the chest invading the chest wall, aorta, vena cava, and lung tissue. The patient soon died from diabetic complications in spite of anti-infection treatment. The tumor was composed of large areas of necrosis and anaplastic neoplastic giant cells with high mitotic activity, and osteoclast-like cells; there was marked inflammatory cell infiltration. The anaplastic neoplastic giant cells were immunoreactive for CKpan, CD5, CD45, VIM, and p53. Approximately 50% to 60% of the tumor cells showed immunoreactivity for Ki-67. In situ hybridization for Epstein-Barr virus-encoded RNA was negative for tumor cells and nonneoplastic osteoclastic giant cells. Because this tumor is very rare, extensive clinical, radiological, and morphological examinations as well as immunohistochemical studies are essential to make the diagnosis.