Polymorphous low-grade XXXX of the major salivary glands: report of three cases in an unusual location.

@entity1 @entity851 @entity5 @entity2281 @entity538 @entity876 @entity7050 @entity3 @entity420 @entity5123
AIMS: Polymorphous low-grade @entity420 ( @entity7050 ) is the second most common type of @entity5 in minor salivary glands. Its origin in major salivary glands is considered exceedingly rare. Herein, we present three cases of de novo @entity7050 arising in major salivary glands. METHODS AND RESULTS: Three cases of @entity7050 were identified in a large series of primary @entity5 of major salivary glands. We investigated their clinicopathological profiles, including immunohistochemical features. The three @entity1 (two @entity1 and one @entity1 ) were 51, 65, and 79 years old. The @entity5 were 20-30 mm large; two were in the parotid gland and one in the submandibular gland. Histologically, all the @entity5 had a polymorphous architectural pattern showing predominantly solid, tubular, and cribriform features and @entity851 . Papillary areas were observed focally in two @entity5 and an 'Indian-file' array in one. The @entity5 cells had a bland cytological appearance and low mitotic count. Two @entity5 showed @entity3 . No preexisting @entity5123 was identified. In all cases, @entity5 cells were positive for epithelial markers, @entity2281 protein, and vimentin but negative for @entity538 . Proliferative activities assessed with the Ki67 labelling index were 4.3%, 7.1%, and 7.6%; no @entity876 overexpression was observed. Two @entity1 had local recurrence, but none had @entity3 or died of @entity5 . CONCLUSIONS: PLGAs arising in major salivary glands and those in minor salivary glands have similar clinicopathological and immunohistochemical characteristics. It is important to recognize that @entity7050 can occur ab initio in the major salivary glands, although it is extremely rare.
