[From metastases to the search of primary tumor]

A metastasis may be the first sign of a malignant tumor. Most commonly this is a pathologically enlarged lymph node, but other symptoms caused by metastases such as pathologic bone fractures may also produce the first symptom of the disease. When searching for the primary tumor, the site of the metastasis and the patient's clinical data must be taken into consideration. Along with possible additional investigations, imaging studies and a biopsy taken from the metastasis lead to diagnosis in 90% of cases. The origin of metastasized tumors remains unraveled in approximately 3 to 5% of cases.