Chordomas: a histological and immunohistochemical study of cases with and without recurrent tumors.

Chordomas are rare, slow-growing and often recurrent neoplasms being composed of various cell types (physaliferous, epitheloid, chondroid), thus, showing a wide range of histological features. To study the relationship between histological and immunohistochemical pattern and biological behavior according to different cell types, the authors studied 33 specimens of 17 patients with and without recurrent tumors. Additionally, the histological features according to nuclear atypia and mitotic activity of both groups were analyzed and compared with each other. Predominance of one cell type was observed in 19 specimens (10 were composed mainly of physaliferous, 8 of the epitheloid and one of chondroid cell type). In 7 cases, areas of chondroid differentiation were present. MIB proliferation index tended not to be higher in recurrent tumors but in cases with nuclear atypia and nuclear pleomorphism seems to be predictive for recurrency. Immunohistochemically, nearly all cell types (physaliferous, epithelial-like and cells of chondroid differentiation) of both recurrent and non recurrent chordomas stained positive for epithel membrane antigen (EMA), cytokeratins (KL1, AE1/AE3), S100, vimentin and negative for HMB45 and desmin. Positive staining for NSE was observed in 70% of cases, however, the chondroid componente stained negative in every case.