Pulmonary carcinosarcoma: diagnostic approach by fine needle aspiration biopsy.

Carcinosarcoma of the lung is an exceedingly uncommon malignancy, possessing both malignant epithelial and mesenchymal elements. There are less than 100 cases reported in the English literature to date. Most of them were diagnosed by autopsy and surgery. Now we present a detailed report of a case with peripheral variant carcinosarcoma diagnosed by percutaneous needle biopsy under sonographic guidance. The clinical, pathologic and immunohistochemical hallmarks of this unique tumor are also reviewed.