[1297] Mammaglobin and S100 Immunoreactivity in Salivary Gland Tumors Other Than Mammary Analogue Secretory Carcinomas

Kalyani R Patel, Isaac H Solomon, Samir K El-Mofty, James S Lewis, Jr., Rebecca D Chernock. Washington University in St Louis, St Louis, MO

Background: Mammary analogue secretory carcinoma (MASC) of the salivary glands is a recently described entity with histopathologic and immunophenotypic features similar to secretory carcinoma (BSC) of the breast. These tumors exhibit a lobulated growth pattern with microcystic and glandular architecture and stain strongly for mammaglobin (MG), vimentin, and S100. Similar to BSC, MASC also harbors a balanced translocation t(12;15)(p13;q25) that results in ETV6-NTRK3 fusion. Immunohistochemistry (IHC) for MG and S100 have been shown to effectively differentiate MASC from its morphologic mimics, especially acinic cell carcinoma. However, limited data exists on the MG and S100 reactivity of other salivary gland tumors, such as polymorphous low grade adenocarcinoma (PLGA), adenoid cystic carcinoma (AdCC), mucoepidermoid carcinoma (MEC), adenocarcinoma, NOS (ANOS) and mucinous adenocarcinoma (MAC).
Design: IHC for MG and S100 was performed on PLGA, AdCC, MEC, ANOS and MAC. Staining strength (weak, moderate, strong) and extent (1+ = 1-25%, 2+ = >25-50%, 3+ = >50-75%, 4+ = >75%) were evaluated. Cases with >1+ intensity and >1+ extent for both MG and S100 were analyzed by FISH using the ETV6 (12p13) breakapart probe.
Results: Fifteen cases each of PLGA, AdCC, and MEC, 2 cases of ANOS and 1 case of MAC were identified. The clinical parameters are summarized in table 1. Positive staining for both S100 and MG was seen in 9/15 PLGA, 2/15 AdCC, 0/15 MEC, 0/2 ANOS and 0/1 MAC (IHC results summarized in table 2); and the 9 PLGAs and 2 AdCC were further analyzed by FISH. There was no correlation between S100 and MG positivity in PLGA or AdCC for both intensity (PLGA p=0.06, AdCCp=0.83) and extent (PLGA p=0.86, AdCC P=0.63). Seven PLGA were negative for the 12p13 translocation by FISH, and two PLGAs were non diagnostic. Both AdCCs were also negative for the translocation

 PLGA (n=15)AdCC (n=15)MEC (n=15)ANOS (n=2)MAC (n=1)
AgeRange (Mean)45-75 (62)32-101 (55)15-75 (48)58-70 (64)64
SexM:F6:95:106:91:10:1
LocationParotid gl01421
 Submandibular gl03000
 Minor salivary gl15101000
 Lacrimal gl01100




 PLGA (n=15)AdCC (n=15)MEC (n=15)ANOS (n=2)MAC (n=1)
S100 intensity>= 2+1310300
S100 extent>= 2+142000
MG intensity>= 2+157821
MG extent>= 2+103721



Conclusions: MG and S100 positivity in salivary gland tumors is not specific to MASC and occurs in a majority of PLGA and a minority of AdCC cases, indicating the need for caution in diagnosing MASC based on IHC in small biopsy material in the absence of cytogenetic confirmation.
Category: Head & Neck

Monday, March 4, 2013 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 193, Monday Morning

 

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