Pleomorphic adenoma originating from submandibular heterotopic salivary gland tissue: A case report and review of the literature

We reported a case of pleomorphic adenoma originating from the submandibular heterotopic salivary gland tissue (HGST) of a 61-year-old man. Histologically, no lymphoid tissue was detected in the tumor. Immunohistochemical examination revealed that the luminal tumor cells of tubuloductal structures were positive for anti-α-amylase antibody. The outer tumor cells of tubuloductal structures and neoplastic myoepithelial cells were stained with K8.12, anti-vimentin antibody, and anti-S-100 protein antibody. No tumor cells reacted with anti-α-smooth muscle actin antibody. These suggest that the tumor cells may be derived from the ductal cells of the extranodal HSGT. No recurrence of the tumor was detected for seven years.