PP017: Clinicopathologic factors affecting outcome in salivary gland Acinic Cell Carcinoma and newly described mammary analogue secretory carcinoma

Abstract

Purpose Mammary Analogue Secretory Carcinoma (MASC) is a newly characterized neoplastic process commonly misdiagnosed as Acinic Cell Carcinoma. Although well-characterized genetically, little information exists regarding the clinicopathologic factors affecting outcome in patients with this disease process. Acinic Cell Carcinoma is a rare entity, and clinicopathologic data has been elucidated from studies with relatively small patient populations. We aim to better understand the characteristics affecting outcome in Acinic Cell Carcinoma patients, and to compare these with patients that have been re-classified with MASC. Materials and Methods Twenty-one patients diagnosed with Acinic Cell Carcinoma were identified from the Medical University of South Carolina cancer registry. Pathological specimens from each patient were then analyzed using fluorescence in situ hybridization (FISH) to detect the ETV6-NRTK3 (12;15) (p13;q25) translocation, which is diagnostic of MASC. Furthermore, radiographic findings were also reviewed for each patient. Demographic information, primary site, presenting symptoms and tumor staging characteristics were obtained along with treatment, recurrence and outcome data for each identified case. Results All patients were treated with primary surgical excision, eleven of which also received adjuvant treatment. The average age at diagnosis was 50.4 years. Parotid glad was the most common site (95%), with one patient demonstrating disease in a minor salivary gland. The majority of patients were female (76%), and most patients were stage I (48%). However, 60% of male patients, and 19% of female patients demonstrated Stage IV disease. Eight patients from our cohort showed increased s100 reactivity, thus making them candidates for FISH analysis. At this point, one case of MASC has been identified with two more cases still to be analyzed. Our confirmed case of MASC was Stage I, which received only primary surgical treatment. Conclusions Although thought to be slightly more aggressive, MASC may have similar clinical outcomes compared to Acinic Cell Carcinoma.