Relapse of Pleomorphic Adenoma from Childhood to Adulthood: Case Report.

Pleomorphic adenoma is rarely seen in childhood. After detailed literature search, we did not come across a case of frequent relapse of this benign tumor from childhood to adulthood. The World Health Organization defines relapse of pleomorphic adenoma as a histologically benign tumor that can have local or distant metastasis. There is one hypothesis how benign tumor can metastasize. According to this hypothesis, probably during the first operative procedure the tissue around the tumor becomes permeable for tumor cells, which can lead to implantation of tumor cells into the surrounding tissue. In this case report, we present a case of a 30-year-old woman with pleomorphic adenoma of the submandibular gland, which relapsed three times. The patient was first operated on in 1993, at the age of 7 years. The first two relapses occurred in 1998 and 2001, at the age of 12 and 15, respectively. The last relapse occurred in 2015, at the age of 29 years. All relapses were localized in the submandibular region on the right side of the neck, where the primary tumor had been operated on.