title: Utility of CK7 and CK20 immunohistochemistry in the detection of synchronous breast and colon carcinoma in a pleural effusion: a case report and supporting survey of archival material.
abstract: We present a case of synchronous breast and colon carcinoma in a pleural effusion, to our knowledge the first such reported case in the English-language literature. The patient was a 55-yr-old white female with known metastatic breast and colon carcinoma who developed a malignant pleural effusion which demonstrated two strikingly different populations of malignant cells by immunohistochemical study of cell block material. One cell population demonstrated a cytokeratin (CK)7+/CK20-/ER+ phenotype, while the other demonstrated a CK7-/CK20+/ER- phenotype, consistent with breast and colon origin, respectively. An immunohistochemical survey of archival breast and colon primary and metastatic carcinomas confirmed the established CK7+/CK20- phenotype of breast and CK7-/CK20+ phenotype of colon primary carcinomas, and the maintenance of this phenotype in metastases thereof. A survey of benign and malignant mesothelial lesions confirmed the absence of staining for estrogen receptor, but showed 6/10 cases weakly positive for CK20, which has not been described in other published series. This unusual case graphically illustrates the utility of cytokeratin subset immunohistochemistry in effusion cytology.
authors.affiliation: Department of Pathology, Pennsylvania Hospital, Philadelphia, Pennsylvania 19107, USA.
authors.forename: G A
authors.initials: GA
authors.lastname: Stopyra
authors.forename: M J
authors.initials: MJ
authors.lastname: Warhol
authors.forename: H A
authors.initials: HA
authors.lastname: Multhaupt
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000556:secondary*; D001943:Breast Neoplasms / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology / Q000556:secondary*; D003110:Colonic Neoplasms / Q000473:pathology*; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D007381:Intermediate Filament Proteins / Q000032:analysis*; D053554:Keratin-20; D053552:Keratin-7; D007633:Keratins / Q000032:analysis*; D008875:Middle Aged; D016066:Pleural Effusion, Malignant / Q000473:pathology*
chemical_list: D007381:Intermediate Filament Proteins; C507499:KRT20 protein, human; C507497:KRT7 protein, human; D053554:Keratin-20; D053552:Keratin-7; D007633:Keratins