Multiple organ tumor lesions analyzed using tumor-related immunostaining in a patient with codon 130 mutation of Cowden syndrome: A case report

Cowden syndrome (CS), also known as multiple hamartoma syndrome, is a rare autosomal dominant genodermatosis. We report a case of a 53-year-old woman diagnosed with CS through phosphatase and tensin homolog (PTEN) gene sequencing, which revealed a mutation in codon 130 of exon 5 (Arg130Ter). A mass appeared on the right buccal mucosa and tongue owing to misbiting. An excision biopsy was conducted, and the sample was analyzed via immunohistochemistry to understand why oral papillomatosis did not progress to malignancy. A review of PubMed identified 21 cases of CS with Arg130Ter mutation. No predilection for women was observed, with an equal distribution between men and women. The incidence rates of thyroid, breast, and urogenital neoplasms in patients with Arg130Ter mutation were higher than those in all patients with CS. Additionally, patients with the Arg130Ter mutation were diagnosed at a younger age than that in all patients with CS. Histopathological examination of the oral mucosa lesions revealed papillary fibroepithelial hyperplasia. Immunohistochemistry revealed negative results for PTEN, MIB-1, and S-100, but positive results for p53 and Bcl-2 in some epithelial cells. These results suggest that symptoms appear at a younger age and tend to be more severe, with p53 as a factor that suppresses malignant transformation in patients with Arg130Ter mutation in CS.