It is important to determine the type and/or site of origin of metastatic tumors for optimal clinical management.
To summarize the use of currently available immunohistochemical markers in the evaluation of metastatic tumors.
Review of relevant literature on immunohistochemical evaluation of tumors and the author's personal experience.
Immunohistochemistry is an important ancillary technique for evaluation of metastatic tumors and should be used in the context of routine morphology and clinical information. While a single marker may be used to support a known or suspected site of origin, a carefully constructed panel is strongly recommended, particularly for tumors of morphologically uncertain lineage or origin.