[93] Mucinous Variant of Invasive Micropapillary Carcinoma (MIMPC) of the Breast – Analysis of Clinicopathologic Features in Comparison with Pure Mucinous and Invasive Micropapillary Carcinoma (IMPC).

Geza Acs, Nicole N Esposito, Christine Laronga. Ruffolo Hooper & Associates, Tampa, FL; Moffitt Cancer Center, Tampa, FL

Background: IMPC of the breast are aggressive tumors frequently showing lymphatic invasion and nodal metastasis. MIMPC, a rare subtype of IMPC, is frequently confused with invasive mucinous carcinoma (IMC). Limited data suggest that MIMPC is more aggressive compared to IMC, suggesting that their distinction has clinical importance. We compared the clinicopathologic features of MIMPC to IMPC and usual IMC in a prospective series of breast cancers.
Design: We selected 209 invasive breast carcinomas (43 IMC, 20 MIMPC and 146 IMPC) for the study. All H&E slides were reviewed and histologic tumor features were determined according to established criteria. Follow-up of patients was performed on the basis of medical records. The clinicopathologic features and outcome of MIMPC were compared to IMC and IMPC.
Results: The results are summarized in the Table. At a mean follow-up of 32.7 months, tumor recurrence was observed in 21 (10%) cases (0 IMC, 3 MIMPC and 18 IMPC). Recurrence free survival was significantly lower in MIMPC and IMPC compared to IMC (p=0.0228 and p=0.0385, respectively).

Summary of results
 IMC (n=43)MIMPC (n=20)IMPC (n=146)p
Size (cm)1.3 (1.4±0.1)1.8 (2.8±0.6)2.0 (3.0±0.2)0.0028
Grade (%)Low22 (51.1)3 (15.0)14 (9.6)<0.0001
 Intermediate19 (44.2)15 (75.0)79 (54.1) 
 High2 (4.7)2 (10.0)53 (36.3) 
Lymphatic invasion (%)Absent42 (97.7)7 (35.0)45 (30.8)<0.0001
 Present1 (2.3)13 (65.0)101 (69.2) 
Nodal metastasis (%)Absent40 (93.0)8 (40.0)38 (26.0)<0.0001
 Present3 (7.0)12 (60.0)108 (74.0) 
ER status (%)Positive43 (100.0)20 (100.0)127 (87.0)0.0143
 Negative0 (0.0)0 (0.0)19 (13.0) 
PR status (%)Positive38 (88.4)15 (75.0)109 (74.6)0.1601
 Negative5 (11.6)5 (25.0)37 (25.4) 
HER2 status (%)Positive2 (4.7)2 (10.0)23 (15.8)0.149
 Negative41 (95.3)18 (90.0)123 (84.2) 



Conclusions: MIMPC are aggressive tumors showing clinicopathologic features and behavior similar to IMPC, significantly worse compared to IMC. Given the difference in biologic behavior, distinction of MIMPC from IMC is important for the appropriate clinical management of patients.
Category: Breast

Monday, February 28, 2011 1:00 PM

Poster Session II # 56, Monday Afternoon

 

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