Evaluation of the diagnostic utility of an immunohistochemical panel (MYB, MYBL1, β-catenin, and LEF1) in basaloid tumors of the salivary glands.

Salivary gland tumors, including adenoid cystic carcinoma (ACC), pleomorphic adenoma (PA), basal cell adenoma (BCA), and basal cell adenocarcinoma (BCAC), share histologic features, making differential diagnosis difficult. However, these tumors differ in biological behavior, treatment strategy, and prognosis, so accurate pathological diagnosis is of great significance. In this study, we used a panel of immunohistochemical antibodies (MYB, MYBL1, β-catenin, and LEF1) to distinguish the abovementioned salivary basaloid tumors. For ACC, 80% (16/20) of cases were MYB-positive, and β-catenin was essentially negative. The BCAs and BCACs were characterized by frequent nuclear β-catenin and LEF1 expression, with positive rates 55% (16/29) and 76% (22/29), respectively. PAs were almost negative for the makers, except for a few cases with LEF1 (3/20) and MYB (1/20) positivity. MYB demonstrated a sensitivity of 80% and a specificity of 94% for ACCs. MYBL1 was negative in all included tumors. LEF1 exhibited a sensitivity of 76% and a specificity of 90% for BCAs and BCACs. β-catenin showed a low sensitivity (55%) but a high specificity (100%) for these tumors. Combined use of LEF1 and β-catenin improved sensitivity (90%) but resulted in a medium specificity (93%). In conclusion, the proposed immunohistochemical panel can improve diagnostic accuracy in basaloid tumors of the salivary glands.