title: Breast cancer with neuroendocrine differentiation detected by unique staining pattern of neoplastic cells in hercep test.
abstract: Hercep Test (DAKO) is an immunohistological screening kit to select cases of advanced breast cancer with indication for treatment with a humanized mouse monoclonal antibody to human epidermal growth factor receptor-2, trasthzumab (Herceptin). We report a case of an 84-year-old female with invasive ductal carcinoma of the right breast, whose neoplastic cells showed a unique staining pattern in Hercep Test. The cells showed an intracytoplasmic fine granular staining pattern, instead of the membranous pattern of typical breast cancer cells. This unique staining pattern suggested some special features of the neoplastic cells. This case was finally diagnosed as invasive ductal carcinoma with focal neuroendocrine differentiation by subsequent imunohistochemical and electron microscopic examinations. The neoplastic cells showed positive reactivity for grimelius stain, chromogranin A, synaptophysin, and neuronspecific enolase, as well as electron-dense neurosecretory granules (up to 150 nm in diameter). This unique staining pattern of the neoplastic cells with Hercep Test is a useful clue to detect breast cancer with neuroendocrine differentiation, which is likely to be missed in routine examination. Clinical and pathologic findings including immunohistochemical and ultrastructural findings of this case are reported, together with a brief review of the literature.
authors.affiliation: Department of Pathology, Nippon Medical School Chiba Hokusoh Hospital. j-mieda@nms.ac.jp
authors.forename: Junko
authors.initials: J
authors.lastname: Mieda
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohaki
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Oguro
authors.forename: Hideki
authors.initials: H
authors.lastname: Shimizu
authors.forename: Kumi
authors.initials: K
authors.lastname: Akasaka
authors.forename: Akinori
authors.initials: A
authors.lastname: Kyomoto
authors.forename: Mie
authors.initials: M
authors.lastname: Kurokawa
authors.forename: Satoru
authors.initials: S
authors.lastname: Arai
authors.forename: Osamu
authors.initials: O
authors.lastname: Mori
authors.forename: Susumu
authors.initials: S
authors.lastname: Okada
authors.forename: Syoji
authors.initials: S
authors.lastname: Kyono
authors.forename: Noritake
authors.initials: N
authors.lastname: Tanaka
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D018278:Carcinoma, Neuroendocrine / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D009378:Neoplasms, Multiple Primary; D011933:Reagent Kits, Diagnostic; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D000068878:Trastuzumab
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D011933:Reagent Kits, Diagnostic; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab