Breast cancer with neuroendocrine differentiation detected by unique staining pattern of neoplastic cells in hercep test.
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.
Mieda
Junko
J
Department of Pathology, Nippon Medical School Chiba Hokusoh Hospital. j-mieda@nms.ac.jp
Ohaki
Yoshiharu
Y
Oguro
Tatsuo
T
Shimizu
Hideki
H
Akasaka
Kumi
K
Kyomoto
Akinori
A
Kurokawa
Mie
M
Arai
Satoru
S
Mori
Osamu
O
Okada
Susumu
S
Kyono
Syoji
S
Tanaka
Noritake
N
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
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D011933:Reagent Kits, Diagnostic; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab