Bone lesions - diagnostic approach using immunohistochemistry and molecular pathology.

Immunohistochemistry and molecular pathology play an essential role in the diagnosis of some focal bone lesions. These techniques may greatly help to distinguish primary bone tumors from metastatic diseases and allow a biologically important refinements in subclassification of round cell sarcomas. Recently, the diagnostic accuracy of organ and tumor specific antibodies has improved significantly. Knowledge of new type of antibodies and their meaningful use enables an accurate classification of the most undifferentiated carcinomas of unknown primary. However, the interpretation of immunohistochemical stains and molecular genetic analysis can be difficult in bone biopsies due to previous decalcification. This article summarizes the most important algorithmic approach to the diagnosis of bone tumors. It outlines the most frequently used tissue-specific antibodies. New advances in the understanding of bone tumorigenesis are also discussed.