Other carcinoma subtypes, WHO classified
Invasive micropapillary

Topic Completed: 1 September 2012

Minor changes: 4 July 2020

Copyright: 2002-2019,, Inc.

PubMed search: Micropapillary carcinoma [title] breast

Monika Roychowdhury, M.D.
Page views in 2019: 10,444
Page views in 2020 to date: 7,195
Cite this page: Roychowdhury M. Invasive micropapillary. website. Accessed August 6th, 2020.
Definition / general
  • Tumor composed of small clusters of cells within clear stromal spaces resembling dilated vascular channels
  • First described by Tavassoli (Mod Pathol 1993;6:660)
  • Rare, < 2% of invasive breast cancers have substantial micropapillary pattern
  • Mean age 59 years, range 25 - 92 years
Clinical features
  • Morphologically similar to micropapillary tumors of bladder, lung and major salivary glands
  • May be caused by reversal of cell polarity and MUC1 expression, resulting in detachment of tumor cells from stroma, promoting their spread and leading to early nodal metastases (Mod Pathol 2004;17:1045)
  • Sialyl Lewis X / CD15s, the ligand of E-selectin, also exhibits reversed cell polarity in these tumors (Int J Surg Pathol 2010;18:193)
  • Tumor infiltrating lymphocytes usually lack cytotoxic phenotype (Mod Pathol 2008;21:1101)
  • Increased expression of CD146 and microvessel density (Pathol Res Pract 2011;207:739)
Prognostic factors
  • Very aggressive with poor prognosis (Adv Anat Pathol 2004;11:297)
  • 95% have lymph node metastases at presentation
  • 70% recur, 50% die of disease
  • Similar prognosis as other breast carcinoma subtypes if node status, tumor size and other classic prognostic markers are considered (Hum Pathol 1999;30:1459)
  • Focal component found in 6% of all breast carcinomas - these cases have same poor prognosis regardless of amount of micropapillary component (Mod Pathol 2001;14:836, Am J Clin Pathol 2006;126:740); exception is that presence of micropapillary pattern in mucinous / colloid carcinoma of breast may have no clinical significance (Int J Surg Pathol 2008;16:251)
  • Presence of micropapillary features and retraction artifact in core biopsies predicts nodal metastases (Am J Surg Pathol 2009;33:202)
Case reports
Gross description
  • Mean tumor size 2 cm, range 0.1 to 10 cm
  • Lobulated outline
Microscopic (histologic) description
  • Well formed, angular and avascular papillary clusters, or morula-like epithelial groups of cells without a fibrovascular core floating in aqueous or mucinous material in lymphatic-like spaces (but without a definite lining)
  • Cells have abundant eosinophilic cytoplasm, round vesicular nuclei and prominent nucleoli
  • Also fibrocollagenous stroma
  • Extensive true angiolymphatic invasion
  • Often psammoma bodies
  • Variable histologic grade
  • Minimal mitotic activity, no necrosis and no lymphocytic inflammation
Microscopic (histologic) images

Case of the Week #4

Low power

High power

Nodal metastases

MUC1 stain

Images hosted on other servers:

Various images

With siliconoma

Low power


Cytology description
Positive stains
  • MUC1 on stroma facing surface of cell clusters [basal], which accentuates outlines of micropapillary units to form a distinct band on this surface
  • HER2 (95%), p53 (70%), bcl2 (70%), ER and PR (20% - 80%) and GCDFP-15 (30%)
Negative stains
Electron microscopy description
  • Secretory activity in stroma facing surface of tumor cells
Molecular / cytogenetics description
  • Mixed tumors have genetic profiles more similar to pure tumors than to ductal carcinoma (J Pathol 2009;218:301)
  • High cyclin D1 expression, high proliferation rates and MYC (8q24) amplification (J Pathol 2008;215:398)
Differential diagnosis
Back to top