title: Breast Tumor Resembling Tall Cell Variant of Papillary Thyroid Carcinoma: A Solid Papillary Neoplasm With Characteristic Immunohistochemical Profile and Few Recurrent Mutations.
abstract: OBJECTIVE
  Breast tumor resembling tall cell variant of papillary thyroid carcinoma (BTRPTC) is a rare breast lesion that is unrelated to thyroid carcinoma. Morphologically, it shows a solid papillary lesion with bland cytology, eosinophilic/amphophilic secretions, nuclear grooves, reversal of nuclear polarity (recently described), and nuclear inclusions. Clinical course is often uneventful with few exceptions reported in the literature. Herein, we report three additional cases.
  
  
  METHODS
  Immunohistochemical staining and next-generation sequencing was performed on all three cases.
  
  
  RESULTS
  The lesional cells on all cases were positive for cytokeratin 5 and S100, with weak expression/lack of estrogen receptor. No staining was observed for myoepithelial markers (p63 and myosin heavy chain) around the lesion. IDH2 mutations were identified in two cases at nucleotide 172 (cases 1 and 3). ATM gene mutation was identified in cases 2 and 3 and PIK3CA mutation in case 3. All patients are currently without disease.
  
  
  CONCLUSIONS
  BTRPTC is a slow-growing neoplastic lesion that needs to be distinguished from other papillary lesions for optimizing therapy.
authors.affiliation: From the Magee-Womens Hospital of University of Pittsburgh Medical Center, Pittsburgh, PA.
authors.forename: Rohit
authors.initials: R
authors.lastname: Bhargava
authors.affiliation: McGill University, Montreal, Canada.
authors.forename: Anca V
authors.initials: AV
authors.lastname: Florea
authors.affiliation: McGill University, Montreal, Canada.
authors.forename: Manuela
authors.initials: M
authors.lastname: Pelmus
authors.affiliation: From the Magee-Womens Hospital of University of Pittsburgh Medical Center, Pittsburgh, PA.
authors.forename: Miroslawa W
authors.initials: MW
authors.lastname: Jones
authors.affiliation: From the Magee-Womens Hospital of University of Pittsburgh Medical Center, Pittsburgh, PA.
authors.forename: Marguerite
authors.initials: M
authors.lastname: Bonaventura
authors.affiliation: University of Pittsburgh Medical Center-Presbyterian, Pittsburgh, PA.
authors.forename: Abigail
authors.initials: A
authors.lastname: Wald
authors.affiliation: University of Pittsburgh Medical Center-Presbyterian, Pittsburgh, PA.
authors.forename: Marina
authors.initials: M
authors.lastname: Nikiforova
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000737:chemistry / Q000235:genetics / Q000473:pathology*; D002277:Carcinoma / Q000473:pathology*; D002291:Carcinoma, Papillary; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053555:Keratin-5 / Q000032:analysis; D008565:Membrane Proteins / Q000032:analysis; D008875:Middle Aged; D009154:Mutation; D018995:Myosin Heavy Chains / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000473:pathology*
chemical_list: C081876:CKAP4 protein, human; D053555:Keratin-5; D008565:Membrane Proteins; D011960:Receptors, Estrogen; D018995:Myosin Heavy Chains
keywords: ATM; Breast tumor resembling tall cell variant of papillary thyroid carcinoma; CK5; ER; IDH2; Myoepithelial markers; PIK3CA mutations; Reverse nuclear polarity; Solid papillary neoplasm