title: Metaplastic variant of invasive micropapillary breast carcinoma: a unique triple negative phenotype.
abstract: Invasive micropapillary carcinomas (IMC) and metaplastic breast carcinoma (MBC) have different clinicopathologic features. This study reports an unusual case of multifocal grade III IMC associated with MBC component in a 35-year-old woman. MBC was vimentin positive, pancytokeratin negative, and showed focal p63 positivity. Immunostains for estrogen and progesterone receptor, and fluorescence in situ hybridization for Her2/neu amplification were negative. All the left axillary lymph nodes dissected were positive for metastatic carcinoma with ductal and IMC patterns, but without metaplastic component. Postmastectomy computed tomography and magnetic resonance imaging scans showed metastases to lungs, liver, brain, and vertebrae. The biologic behavior of tumor was in accordance with histology, so that the nodal and distant metastases were testament to the underlying inherently aggressive IMC, whereas large tumor size and triple negativity reflected the features of MBC. To the best of the authors' knowledge, this is the first report of a metaplastic variant of invasive micropapillary breast carcinoma with triple negative phenotype.
authors.affiliation: Georgia Health Sciences University, Augusta, GA 30912, USA.
authors.forename: Gitika
authors.initials: G
authors.lastname: Aggarwal
authors.forename: Michelle Dian
authors.initials: MD
authors.lastname: Reid
authors.forename: Suash
authors.initials: S
authors.lastname: Sharma
mesh_terms: D000231:Adenocarcinoma, Papillary / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D000328:Adult; D001365:Axilla; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D003131:Combined Modality Therapy; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008198:Lymph Nodes / Q000473:pathology; D008408:Mastectomy; D008679:Metaplasia; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D009378:Neoplasms, Multiple Primary; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone