Basal cell adenoma of salivary glands with a focal cribriform pattern: clinicopathologic and immunohistochemical study of 19 cases of a potential pitfall for diagnosis.

Cribriform type of salivary basal cell adenoma (cBCA) is relatively rare and problematic in distinction from adenoid cystic carcinoma (AdCC). The aim of this study was to investigate the clinicopathology and immunoprofile of cBCA. Nineteen cases of cBCA with at least a 30% area of cribriform structure under microscope were analyzed by the description of their histopathologic and immunohistochemical features using the antibodies of matrix metalloproteinase-9 (MMP9), CK8&18, calponin, SMA, S100, P63, CD117, and laminin. The patients of cBCA ranged from 24 to 71 years with a distinct predilection for females (79%). The tumor was well-circumscribed and had no recurrent tendency after a local excision followed by a median of 67 months. Enhanced computed tomography (CT) showed that the tumor was rich in blood supply. Microscopically, it was mainly composed by the basaloid cells with the peripheral palisading. The cells around the cribriform pattern expressed P63 protein and had almost no immunoreactivity for calponin, SMA, S100, or CK8&18. The expression level of MMP9, laminin, and CD117 were significantly lower in cBCA than those in AdCC. Good circumscription, lack of infiltrative properties, and absence of MMP9, laminin, CD117, and myoepithelial marker (SMA, S100 and calponin) in the cells around the cribriform spaces, are the most reliable points for differential diagnosis of cBCA from AdCC.