Images in Clinical Medicine

Spindle-Cell Thymoma

Oz M. Shapira, M.D., and John M. Kasznica, M.D.

N Engl J Med 2003; 349:1442October 9, 2003

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Article

A 77-year-old Chinese woman presented with an abnormality on a chest film obtained as part of her screening for immigration to the United States. A posteroanterior film showed a well-circumscribed mass, 8 cm in diameter, in the lower region of the anterior mediastinum and extending into the right hemithorax (Panel A, arrows). The mass was completely excised through a right thoracotomy. There was no evidence of invasion of adjacent structures. Gross examination of a section of the specimen showed irregular, friable areas of hemorrhage and necrosis (Panel B). Microscopical examination showed mixed spindle and polygonal cells arranged in ill-defined bundles (Panel C; hematoxylin and eosin, ×250), a finding that is characteristic of spindle-cell thymoma. Spindle-cell thymomas are usually well-encapsulated tumors that grow slowly. The long-term prognosis is favorable, although the tumors may be associated with myasthenia gravis and various hematologic paraneoplastic syndromes.

Oz M. Shapira, M.D.
John M. Kasznica, M.D.
Boston Medical Center, Boston, MA 02118