title: Neoplastic pleocytosis in a dog with metastatic mammary carcinoma and meningeal carcinomatosis.
abstract: A 12-year-old female spayed Labrador Retriever was presented with a history of seizures and abnormal vocalization. Approximately 1 year before presentation, multiple mammary cysts had been surgically excised. A mammary mass was noted on physical examination, and 2 separate parenchymal brain lesions were found on imaging studies. Cerebrospinal fluid (CSF) collected from the cisterna magna was analyzed, and abnormalities included moderate pleocytosis with atypical discrete round cells that occasionally formed loose clusters. The dog was euthanized, and on necropsy a primary solid mammary carcinoma was identified as well as multiple metastatic foci in the brain with diffuse meningeal involvement. The cells in the CSF had a morphologic appearance similar to the cells in the primary mammary tumor and in the metastatic tumors in the brain. On immunostaining, cells from the primary mammary tumor, the brain tumors, and the CSF expressed cytokeratin. The CSF cells did not express CD18, CD3, or CD79a. A final diagnosis of mammary carcinoma with brain metastasis and meningeal carcinomatosis was made.
authors.affiliation: Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA. behling.kelly@vetmed.wisc.edu
authors.forename: Erica
authors.initials: E
authors.lastname: Behling-Kelly
authors.forename: Sophie
authors.initials: S
authors.lastname: Petersen
authors.forename: Anantharaman
authors.initials: A
authors.lastname: Muthuswamy
authors.forename: Julie L
authors.initials: JL
authors.lastname: Webb
authors.forename: Karen M
authors.initials: KM
authors.lastname: Young
mesh_terms: D000818:Animals; D003937:Diagnosis, Differential; D004283:Dog Diseases / Q000134:cerebrospinal fluid / Q000175:diagnosis / Q000473:pathology*; D004285:Dogs; D005260:Female; D007964:Leukocytosis / Q000473:pathology / Q000662:veterinary*; D015674:Mammary Neoplasms, Animal / Q000134:cerebrospinal fluid / Q000175:diagnosis / Q000473:pathology*; D055756:Meningeal Carcinomatosis / Q000134:cerebrospinal fluid / Q000473:pathology / Q000662:veterinary*; D009362:Neoplasm Metastasis