Establishment of a primary culture of polymorphous low grade adenocarcinoma cells

Comparison of p63/p40 Expression With Myoepithelial Markers in Minor Salivary Gland Tumors

The present study aimed to compare the expression of p63/p40 with smooth muscle actin (SMA) and vimentin (VIM) by myoepithelial cells in minor salivary gland tumors. Fifty-two formalin-fixed paraffin-embedded samples of minor salivary gland tumors derived from intercalated duct (pleomorphic adenoma [PA], adenoid cystic carcinoma [ACC], epithelial-myoepithelial carcinoma [EMC], polymorphous adenocarcinoma [PAC], and secretory carcinoma [SC]) and 3 samples of minor salivary gland tumors derived from excretory duct (mucoepidermoid carcinoma [MEC]) were evaluated by means of immunohistochemistry. The data were analyzed qualitatively. The results indicated that p63 and p40 expression were detected in myoepithelial cells present in PA, ACC, and EMC. However, both proteins were also observed in squamous areas of PA and all cases of MEC. SMA were noticed in some myoepithelial cells of PA, ACC, and EMC. Expression of SMA was negative in the other salivary gland tumors evaluated. VIM was constantly expressed by myoepithelial cells in PA, ACC, and EMC. VIM was also observed in cells of PAC and SC, but not in squamous areas of PA and MEC. In conclusion, p63 expression is almost comparable with VIM in detecting myoepithelial cells, an immunolabeling pattern not followed by p40, and consequently, caution has to be taken during the interpretation of salivary gland tumor exhibiting an p63/p40 phenotype in order to avoid a misdiagnosis.

Palatal Polymorphous Adenocarcinoma with High-Grade Transformation: A Case Report and Literature Review

Polymorphous adenocarcinoma (PAC) is the second most common intraoral malignant neoplasm of the minor salivary glands. However, it is very rare for PAC to show high-grade transformation (HGT) and to our knowledge, the English literature only seven reported cases. HGT tends to be observed when PAC recurs, and it is extremely rare to be seen at initial presentation. Here we report a 43-year-old Japanese male patient with PAC of the right palate showing HGT at initial presentation. Histopathologically, the tumor was characterized by a prominent solid and papillary-cystic growth pattern, with nuclear atypia and necrosis in area of HGT. The immunohistochemical staining pattern was consistent with PAC, as the tumor cells showed diffuse positivity for cytokeratin, vimentin and S-100, and focal positivity for bcl-2, ɑ-SMA and EMA. The tumor cells in HGT areas were markedly positive for AR and Ki-67 (about 40%/HPF), and also focally positive for cyclin D1 and p53, whereas HER2/neu, ER, PgR, p63, D2-40, GCDFP-15, and mitochondria were negative. Here we present a very rare case of palatal PAC with HGT at initial presentation.