Micropapillary carcinoma of the breast

Definition

Epidemiology

About 2.5% of all breast carcinomas are of micropapillary type¹. Patients are adult, with a mean age of about 50 years¹.

Histopathology

There are infiltrating micropapillae without a fibrovascular core: the micropapillae are surrounded by clear spaces². These intermix with tubulo-alveolar clusters separated by fibrocollagenous stroma. Psammoma bodies vary from rare⁴ to common⁷. A minority of cases are combined with a ductal, neuroendocrine or mucinous component, the cells within the mucin also having a micropapillary configuration. Lymphovascular invasion is common, with a high rate of nodal metastases. Skin involvement is common⁷.

Metastases and recurrences retain the micropapillary architecture^2,8.

Immunohistochemistry

		micropapillary carcinoma	invasive ductal carcinoma NOS
	Oestrogen receptors	21/311, 24/333, 68/754, 71%5	23/601
	Progesterone receptors	19/311, 15/333, 52/744	19/601
	bcl-2	23/333
	p53	15/311, 6/87	22/601
	c-erbB-2	17/311, 12/333	31/601
	Ki67 proliferation index	mean = 26% (31 cases)1	mean = 16% (60 cases)1
	HER-2/neu protein	13/224
	EMA	preferentially stains the outside of the micropapillae10

Cytogenetics

Loss of the short arm of chromosomes 8 is common⁹.

Differential diagnosis

Other breast carcinomas:

• invasive papillary carcinoma: there is a true papillary structure and low grade cytology.

• colloid carcinoma: mucin secretion is a component of some micropapillary carcinomas. A thorough search must be made to exclude any micropapillary component.

Metastases:

• ovarian micropapillary serous carcinoma

• micropapillary transitional cell carcinoma of bladder

• micropapillary carcinoma of the colon: CK7-/CK20-.

• micropapillary adenocarcinoma of lung

Prognosis

The rates of local recurrence, distant metastases and death from disease have all been reported to be higher than for ductal carcinoma¹. However, stage for stage, the prognosis may be similar to that of ductal carcinoma⁶.

References

¹ Zekioglu, O., Y. Erhan, et al. (2004). "Invasive micropapillary carcinoma of the breast: high incidence of lymph node metastasis with extranodal extension and its immunohistochemical profile compared with invasive ductal carcinoma." Histopathology 44(1): 18-23.

² Siriaunkgul, S. and F. A. Tavassoli (1993). "Invasive micropapillary carcinoma of the breast." Mod Pathol 6(6): 660-2.

³ Luna-More, S., F. de los Santos, et al. (1996). "Estrogen and progesterone receptors, c-erbB-2, p53, and Bcl-2 in thirty-three invasive micropapillary breast carcinomas." Pathol Res Pract 192(1): 27-32.

⁴ Walsh, M. M. and I. J. Bleiweiss (2001). "Invasive micropapillary carcinoma of the breast: eighty cases of an underrecognized entity." Hum Pathol 32(6): 583-9.

⁵ Nassar, H., T. Wallis, et al. (2001). "Clinicopathologic analysis of invasive micropapillary differentiation in breast carcinoma." Mod Pathol 14(9): 836-41.

⁶ Paterakos, M., W. G. Watkin, et al. (1999). "Invasive micropapillary carcinoma of the breast: a prognostic study." Hum Pathol 30(12): 1459-63.

⁷ Middleton, L. P., F. Tressera, et al. (1999). "Infiltrating micropapillary carcinoma of the breast." Mod Pathol 12(5): 499-504.

⁸ Tresserra, F., P. J. Grases, et al. (1999). "Invasive micropapillary carcinoma. Distinct features of a poorly recognized variant of breast carcinoma." Eur J Gynaecol Oncol 20(3): 205-8.

⁹ Thor, A. D., C. Eng, et al. (2002). "Invasive micropapillary carcinoma of the breast is associated with chromosome 8 abnormalities detected by comparative genomic hybridization." Hum Pathol 33(6): 628-31.

¹⁰ Putti TC, Pinder SE, Elston CW, et al. Breast pathology practice: most common problems in a consultation service. Histopathology 2005; 47:445-57

This page last revised 15.12.2005.

©SMUHT/PW Bishop