Atypical teratoid/rhabdoid tumor (AT/RT) is a rare malignant tumor that occurs in children especially in the first few years of life. It is a tumor with high malignancy, rapid growth, poor response to treatment, and very poor prognosis. Skin metastasi...
Atypical teratoid/rhabdoid tumor (AT/RT) is a rare malignant tumor that occurs in children especially in the first few years of life. It is a tumor with high malignancy, rapid growth, poor response to treatment, and very poor prognosis. Skin metastasis has been reported very rarely and appears to be a hamartoma pattern mimicking skin tag. Immunohistochemistry is a complex result that is expressed differently in different parts of the body depending on histologic features. Integrase Interactor-1 (INI-1) immunostaining and tumoral and leukocytes INI-1 gene sequencing assays are used as confirmatory tests in cerebral tumors. In skin biopsies, INI-1 immunostaining is used as a confirmatory test. In immunohistochemical staining, loss of INI-1 is characteristic. In our case, a skin examination revealed a cluster of multiple papules with pale erythema on the right side of the back. At 2 months of age, chondromyxoid fibroma was seen on histologic examination. Two months later, he was admitted to the hospital with seizure. After surgery, AT/RT was diagnosed by INI-1 loss of expression in immunochemical staining. Then, additional immunochemical staining was performed on the skin specimens, and INI-1 loss of expression was detected, In patients with macrocephaly, hydrocephalus, and intracranial tumors, loss of expression through INI-1 immunostaining may be helpful in the diagnosis of unusual skin lesions such as polypoid soft fibroma.