We report on an unusual case of laterocervical bilateral metastatatic masses with unknown clinical, radiological or computer tomographicic detected primary site of origin. Cancer of an unknown primary site is a clinical syndrome, accounting for 2%-5% of patients with cancer. The peculiarities of our case are its evolution as fast-growing bilateral tumor masses with involvement of other neck structures and its unexpected origin from the lung, certified by complementary immunohistochemical tests following surgery, in the absence of any other clinical signs or any detectable lung tumor mass by radiological or computer tomographic tests.