LEF-1: Diagnostic utility in distinguishing basaloid neoplasms of the salivary gland.

BACKGROUND: Lymphoid enhancer binding factor 1 (LEF-1) has recently been reported as a potential immunohistochemical (IHC) marker for basal cell adenoma (BCA) and other salivary gland tumors, which may contribute to an increased accuracy in differentiating basaloid salivary gland neoplasms. We evaluated the utility of LEF-1 in fine needle aspiration (FNA) and resection specimens to distinguish pleomorphic adenoma (PA), BCA, basal cell adenocarcinoma (BCAC), and adenoid cystic carcinoma (ACC) as well as in non-neoplastic salivary gland (NNSG).

METHODS: Cases including 66 PA (35 FNA, 31 resections), 12 BCA (5 FNA, 7 resections), 42 ACC (11 FNA, 31 resections), 1 BCAC FNA, and 10 NNSG (5 FNA, 5 resections) were obtained and stained for LEF-1.

RESULTS: On cell block (CB), 51% of PA and 60% of BCA were LEF-1 positive while 91% of ACC were LEF-1 negative. Among resections, there was a higher percentage of LEF-1 positive PA (84%) and BCA (86%), and a higher percentage of LEF-1 negative ACC (97%). LEF-1 staining had a low to moderate sensitivity for detecting benign basaloid neoplasms on FNA CB and resection specimens (52.5% and 84%, respectively), but a higher specificity (92% and 97% respectively), and positive predictive value (95% and 97% respectively).

CONCLUSION: When comparing benign (PA and BCA) and the most common malignant basaloid salivary gland tumor (ACC), positive LEF-1 favors a benign neoplasm. Additional studies with LEF-1, specifically including other rare basaloid salivary gland neoplasms are needed to further clarify the role of LEF-1 in diagnosing these lesions on FNA.