ABSTRACT
For the vast majority of patients with unknown primary carcinoma (UPC), well defined clinico-pathologic characteristics allowing accurate prognostic are not immediately evident and the identification of reliable prognostic indicators has proven challenging. Only in small numbers of patients the overall similarity of the clinical presentations to that of known primary cancers at a similar stage has resulted in the identification of subsets of patients with clinical and pathological features requiring specific guidelines that may translate into prolonged survival.
