Pancreatic adenocarcinoma with a germline PTEN p.Arg234Gln mutation

A minor fraction of pancreatic ductal adenocarcinoma (PDAC) develops in association with germline mutations of the genes responsible for inherited cancer syndromes. However, the PDAC that has a germline PTEN mutation has not received much attention. Genome-wide whole exome sequencing was performed on germline and somatic DNA from an 82-year-old woman who had developed a solid pancreatic cancer but did not show characteristic findings of PTEN hamartoma tumor syndromes (PHTS). Histology of the resected pancreatic tumor showed unique PDAC findings of primarily dendriform structures and dense fibrous tissue, accompanied by multiple pancreatic intraepithelial neoplasias in the vicinity. The tumor immunohistochemistry revealed a loss of PTEN expression and overexpression of TP53. Exome sequencing revealed a K-ras mutation (p.Gly12Val). Germline exome sequencing revealed a missense mutation of PTEN (p.Arg234Gln), a rare variant with a reported association with cancer development but not with other PHTS phenotypes. To our knowledge, this is the first report of PDAC associated with a germline PTEN mutation, particularly a rare variant (p.Arg234Gln) with cancer risks.