[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 (%)	Low	22 (51.1)	3 (15.0)	14 (9.6)	<0.0001
	Intermediate	19 (44.2)	15 (75.0)	79 (54.1)
	High	2 (4.7)	2 (10.0)	53 (36.3)
Lymphatic invasion (%)	Absent	42 (97.7)	7 (35.0)	45 (30.8)	<0.0001
	Present	1 (2.3)	13 (65.0)	101 (69.2)
Nodal metastasis (%)	Absent	40 (93.0)	8 (40.0)	38 (26.0)	<0.0001
	Present	3 (7.0)	12 (60.0)	108 (74.0)
ER status (%)	Positive	43 (100.0)	20 (100.0)	127 (87.0)	0.0143
	Negative	0 (0.0)	0 (0.0)	19 (13.0)
PR status (%)	Positive	38 (88.4)	15 (75.0)	109 (74.6)	0.1601
	Negative	5 (11.6)	5 (25.0)	37 (25.4)
HER2 status (%)	Positive	2 (4.7)	2 (10.0)	23 (15.8)	0.149
	Negative	41 (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