Résumé
An atypical teratoid/rhabdoid tumor (AT/RT) is a rare malignancy occurring in the first few years of life. This tumor shows rapid growth, a poor response to treatment, and poor prognosis. Cutaneous metastases presents as hamartomatous lesions mimicking skin tags. Immunohistochemical examination shows varied patterns of expression based on the sites of the body affected. Integrase interactor-1 (INI-1) gene sequencing and loss of expression of INI-1 observed with immunostaining can confirm AT/RT. In our patient, the skin lesion was identified at birth. Histopathological examination of the skin lesion could not establish an accurate diagnosis. Two months later, the patient presented with a brain tumor. Immunohistochemical examination of the brain lesion revealed complete loss of INI-1 expression in tumor cells, and the lesion was diagnosed as AT/RT. After that, we can detect the loss of INI-1 expression in the skin on the back. We report a rare case of AT/RT affecting the brain with cutaneous metastasis diagnosed with immunohistochemical staining.