[1279] Primary Signet-Ring Cell (Mucin-Producing) Adenocarcinoma of Minor Salivary Glands: A Clinicopathologic, Immunohistochemical and Molecular Survey

Jassem M Bastaki, Bibianna M Purgina, Sanja Dacic, Raja R Seethala. University of Pittsburgh Medical Center, Pittsburgh, PA

Background: Primary salivary signet-ring cell (mucin-producing) adenocarcinomas (SRCA) are extremely rare and poorly understood. We evaluate the clinicopathologic features of 4 cases and evaluate immunohistochemical and molecular features modeled after common profiles in mucinous/signet ring adenocarcinomas of other sites.
Design: Four cases were retrieved. Histochemical and IHC staining using standard technique was performed and included the following: mucicarime, PASD, AE1/3, CK7, CK20, CK5/6, CAM 5.2, CDX2, ER, AR, PSA, TTF-1, thyroglobulin, mammaglobin, HER2/neu, synaptophysin, chromogranin, actin, AMA, p63, calponin, PsAP, s100, GCDFP, Ki-67 and E-Cadherin. Additionally, fluorescence in situ hybridization for ALK gene rearrangements using a break apart probe 2p23 was performed (Abbott Molecular, Des Plaines, IL). Cases with more than 20% of tumor cells showing a rearrangement were considered positive.
Results: The male:female ratio was 3:1. The mean age was 56 (range: 18-81). Sites involved were buccal mucosa (2), soft palate (1), and deep parotid (1). Perineural and angiolymphatic invasions were present in (3) and (2) cases respectively. The patient with a soft palate tumor had nodal metastasis on presentation. One patient was lost to follow-up, and the remainder, were alive and without disease at time of last follow up (mean 38 months). All cases showed a uniformly univacuolar (signet ring) appearance embedded in a myxoid stroma and were mucicarmine positive. The IHC profile is summarized in Table 1. Three cases showed at least focal p63 staining, and 2 cases were positive for calponin and GCDFP-15. Interestingly, membranous E-cadherin was retained and mammaglobin was positive in all cases. All tumors were negative for ALK rearrangements.

Result of histochemical and immunohistochemical testing
CAM 5.2++++
Negative stains are not shown

Conclusions: Alterations (i.e. loss of E-cadherin, ALK rearrangements) noted in signet ring tumors at other sites are not present in salivary SRCA. The pathogenesis of this lesion is still elusive. The frequent coexpression of some myoepithelial markers and mammaglobin, mucicarmine and GCDFP-15 suggest a possible 'secretory myoepithelial' phenotype.
Category: Head & Neck

Tuesday, March 20, 2012 1:00 PM

Poster Session IV # 163, Tuesday Afternoon


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