Salivary Mucoepidermoid Carcinoma: Clinicopathologic Study of 53 Patients
E Adler, C Sarta, RV Smith, R Owen, J Smith, B Schiff, D Gitler, M Brandwein-Gensler. Montefiore Medical Center, Bronx, NY
Background: Mucoepidermoid carcinoma (MEC) is one of the most common salivary malignancies. We previously published a grading system which modified the AFIP schema by adding the variables of tumor pattern of invasion, lymphovascular invasion, bony invasion and increasing the weighted value for perineural invasion. Our goal is to 1) review the clinicopathologic features of a new cohort and 2) compare the two grading systems.
Design: We searched MMC pathology files (1978-2009) and reviewed cases diagnosed as "MEC". Tumors were graded according to both published criteria. Charts were reviewed for tumor site, stage, treatment, and outcome.
Results: We reviewed 67 tumors; 14 were excluded after reclassification as squamous carcinoma (SCC) (3), high-grade salivary duct carcinoma (HGSDC) (3), low-grade salivary duct carcinoma (1), carcinoma-ex-BMT (1), sebaceous carcinoma (1), carcinoma-not-otherwise-specified (3), cystadenoma (1), and MEC metaplasia in BMT (1). The diagnosis of MEC was confirmed on 53 tumors. Ages ranged from 18-77 (mean 50), female: male ratio was 3:1. Most common sites were parotid (55%), oral cavity (32%), and submandibular gland (9%). Unusual presentations in 2 patients merit mention. One grade I MEC was diagnosed as a benign cyst. This tumor was inadeqately excised and its persistence became manifest 9 years later. This woman is disease-free 3 years after definitive surgery. One woman with grade II parotid MEC presented with a draining cutaneous fistula. The frequencies of grades I, II, & III MEC by our criteria are 36%, 34%, & 30%, respectively. Our criteria upgraded 30% of MEC: 20% from grades I to II, 8% from grades II to III, and 2% from grades I to III. Information on outcome was available on 35 patients. Two patients (grade III, both schemas) died of disease at 12 and 16 months, respectively. One patient is alive with persistent disease. Thirty two patients are disease-free (mean 44 months).
Conclusions: MEC is usually associated with good outcome when appropriately treated. The diagnosis of MEC is unlikely for tumors with extreme pleomorphism, abundant keratinization, or hyalinization. SCC and HGSDC comprised the most common tumors misdiagnosed as MEC. Our proposed grading criteria upgraded 30% of MEC compared to the AFIP criteria, however the limited number of disease-progression events did not allow for comparison of the performance of the two grading classifications.
Category: Head & Neck
Monday, March 22, 2010 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 166, Monday Morning