Usefulness of SOX-10 and EGFR for Pericapsular Evaluation of Pleomorphic Adenomas

Pleomorphic adenoma is a common salivary gland tumor, representing about two-thirds of cases. Surgical excision is the primary treatment, usually leading to a good prognosis. However, there have been occasional reports of recurrence and malignant transformation. These tumors typically have a capsule, but it can be incomplete or invaded. This makes it crucial to examine the relationship between peripheral tumor tissue and cells within the capsule during histopathological examination. A study at Nihon University School of Dentistry Hospital included 44 cases of palatal pleomorphic adenomas, chosen from 50 based on capsule presence and the absence of satellite nodules. Immunohistochemical stains, SOX 10 and EGFR, were used. HE-stained specimens were classified into four groups following Seifert's classification, with Subtype 1 as 'classic type,' Subtype 2 as 'stroma-rich type,' and Subtypes 3 and 4 as 'cellular-rich type.'SOX-10-positive cell ratios varied significantly near the capsule among these groups. EGFR immunoreactive scores were highest in the cellular type, indicating greater biological activity. The study highlights a strong correlation between Seifert's classification and the ratio of tumor-forming myoepithelial cells near the capsule. Cellular type demonstrated the highest IRS, suggesting heightened biological activity, which is supported by SOX-10 and EGFR staining patterns. In summary, this study suggests a link between Seifert's classification and biological activity in minor salivary gland pleomorphic adenomas. Cellular type exhibited a potential for higher biological activity, based on staining patterns and IRS.