Plasmacytoid-Type Cellular Differentiation in Polymorphous Low-Grade Adenocarcinoma.
INTRODUCTION
Polymorphous low-grade adenocarcinoma (PLGA) occurs more frequently in minor salivary glands. The diagnosis of PLGA, in general, is not difficult but in occasional tumors showing limited invasion or in small biopsy specimens, PLGA may be confused with cellular pleomorphic adenoma (PA). Plasmacytoid cells, a usual component of PAs, have been considered helpful for correct tumor identification.


OBJECTIVE
The aim of this study was to verify the frequency (if any) of plasmacytoid-type cellular differentiation (PD) in PLGA.


MATERIALS AND METHODS
Thirty-two cases of PLGA were reviewed. PD was recognized in 2 cases (6.25%), in which immunohistochemical expression of AE1/AE3, CK7, CK14, vimentin, α-SMA, p63, S-100, calponin, GFAP, and Ki-67 was evaluated.


RESULTS
The 2 cases presented conventional areas of PLGA and variable quantities of cells with PD forming aggregates in the stroma and lining ductal structures. Cells with PD showed positivity for AE1/AE3, CK7, S-100, and vimentin and were negative for CK14, calponin, and GFAP in both cases. In case 1, cells with PD did not present α-SMA and p63 positivity whereas in case 2 they were positive, but for α-SMA such reactivity was restricted to cells forming solid aggregates.


CONCLUSION
Although PD in PLGA is rare, it is necessary to be aware of this possibility, particularly in small incisional biopsies and in PLGA with limited invasion, to avoid confusion with cellular PA.
['Dos Santos|Harim Tavares|HT|', 'de Andrade|Bruno Augusto Benevenuto|BA|', 'Egal|Erika Said Abu|ES|', 'Filho|Edson Robles Castilla|ER|', 'Mariano|Fernanda Viviane|FV|', 'Altemani|Albina|A|']
D000230:Adenocarcinoma D008949:Adenoma, Pleomorphic D014408:Biomarkers, Tumor D002454:Cell Differentiation D003937:Diagnosis, Differential D005260:Female D006801:Humans D007150:Immunohistochemistry D008297:Male D008875:Middle Aged D012468:Salivary Gland Neoplasms
polymorphous low-grade adenocarcinoma plasmacytoid cell