Cowden syndrome is an autosomal dominant disorder with a predisposition to multiple benign and malignant tumors with unique oral manifestations. We present a case of Cowden syndrome in a patient diagnosed with breast cancer, traumatic fibromas, bronchial asthma, and multiple papillomatous fibromatosis of the oral cavity. Close association between oral papillomatosis associated with Cowden syndrome and PTEN gene mutation may increase the risk for malignant transformation. Therefore, patients of Cowden syndrome should be monitored carefully for all kinds of cancers. Schlagwörter: Cowden syndrome, oral, paraneoplastic