[Clinicopathologic and immunohistochemical study of atypical teratoid/rhabdoid tumor of central nervous system].

OBJECTIVE

To study the clinicopathologic features and differential diagnosis of atypical teratoid/rhabdoid tumor (AT/RT) occurring in the central nervous system.

METHODS

Two cases of AT/RT were studied by hematoxylin-eosin, reticulin and immunohistochemical staining. The clinical and pathologic features were analyzed and the literatures reviewed.

RESULTS

Histologically, AT/RT was characterized by the presence of rhabdoid cells associated with various degrees of primitive neuroectodermal, epithelial or mesenchymal differentiation. Abundant reticulin fibers and a complex immunophenotype were observed. The tumor cells were positive for vimentin, CD99, epithelial membrane antigen, cytokeratin, glial fibrillary acidic protein, S-100 protein, neurofilament, desmin and smooth muscle actin. They were negative for synaptophysin, MyoD1, placental alkaline phosphatase and HMB45.

CONCLUSIONS

AT/RT is a highly malignant tumor occurring in the central nervous system. It manifests mainly in children and occasionally in adults. The tumor is characterized by a heterogeneous histologic and immunohistochemical phenotype. It needs to be distinguished from a number of central nervous system tumors, including medulloblastoma, primitive neuroectodermal tumor, germ cell neoplasm and rhabdoid meningioma.