[1130] Salivary Duct Carcinoma with or without Micropapillary Components: Clinicopathologic and Immunohistochemical Comparison

YO Hong, KJ Cho, JY Ro. Asan Medical Center, Ulsan College of Medicine, Seoul, Korea; Eulji General Hospital, Eulji University, Seoul, Korea; The Methodist Hospital, Weill Medical College, Cornell University, Houston, TX

Background: Micropapillary (MP) carcinoma has been described in tumors of several organs including breast, lung, colon, ovary and urinary bladder, and reported to be associated with a poor prognosis. We compared the clinicopathologic and immunohistochemical findings of 12 cases of salivary duct carcinoma (SDC) with MP and 14 cases of conventional SDC without MP carcinoma component.
Design: Clinicopathologic findings including age, gender, site, tumor size, and proportion of MP carcinoma component as well as immunohistochemical stain (IHS) findings in 12 SDCMP were compared with 14 cases of SDC without MP carcinoma component. Follow-up data were obtained from all patients with SDCMP and SDC. IHS for CK7, CK20, ER, PR, racemase, HER-2, p53 and ki-67 was performed on tissue microarray blocks in both SDCMP and SDC.
Results: Histologically, the MP component was characterized by small tight cell clusters without fibrovascular core and distributed in clear lacunar spaces. The MP component ranged from 5 to 50% with average 19.2%. The male and female ratio was 9:3 for SDCMP and 12:2 for SDC. The tumor was slightly larger in SDCMP (3.2cm) than SDC (2.9cm). The location of SDCMP was parotid in 7 cases, submandibular in 4 cases and sublingual in 1 case (parotid- 9, submandibular- 4 and sublingual-1 in SDC). Lymphovascular invasion (LVI) was seen in 10 of 12 cases of SDCMP (4/14 cases in SDC) (p<0.05). 10 of 12 patients of SDCMP showed local recurrence and/or metastasis (7/14 patients in SDC) (p<0.05) with only 1 patient of SDCMP is alive and well (7/14 patients in SDC) (p<0.05). IHS results revealed that SDCMP cases were more commonly positive for p53 (67%) and Ki-67 (50%) than in SDC (p53, 50%; Ki-67, 21.4%). Recemase (10/12 and 13/14) and Her-2/neu (8/12 and 10/14) were commonly positive in both SDCMP and SDC. All but one case of SDCMP was positive for CK7 and negative for CK20. Most SDCMP and SDC were negative for ER and PR.
Conclusions: MP component was frequently seen in SDC (12/26 cases, 46.1%). In our study, SDCMP was seen in slightly younger age (59.2 yrs) than in SDC (64.2 yrs), and the tumor size of MPSDC was slightly larger (3.2 cm) than that of SDC (2.9cm). SDCMP showed more frequent LVI, local and distant recurrences, and more frequent p53 and Ki-67 positivity than SDC. Our study indicated that MP histology in SDC is an aggressive histologic variant.
Category: Head & Neck

Monday, March 9, 2009 1:00 PM

Poster Session II # 155, Monday Afternoon