title: Multifocal cutaneous histiocytic sarcoma in a young dog and review of histiocytic cell immunophenotyping.
abstract: A 9-month-old male Great Dane had progressive generalized nodular dermatopathy for several months. There were > 100 raised, alopecic, firm, painful nodules throughout the skin. Aspirates from several lesions yielded moderate numbers of irregularly round or polygonal to spindle-shaped cells with mild to moderate anisocytosis and few inflammatory cells, and the cytologic interpretation was proliferation of mesenchymal or histiocytic cells. On histopathologic examination, nodules were composed of densely packed sheets of round to spindle-shaped cells with mild anisokaryosis and low mitotic activity. Multifocal histiocytic sarcoma with a spindle-cell pattern was diagnosed based on morphologic features and intense expression of CD18. Additional immunophenotypic analysis on frozen sections of tissue confirmed the diagnosis of histiocytic sarcoma; expression of CD18, CD45, CD1a, CD11b, and CD11c, limited expression of Thy-1 (CD90) and CD80, and lack of expression of CD4, CD11d, and CD86 indicated that the cells were likely interstitial dendritic cells; a review of reactive and neoplastic dendritic cells is provided. Based on staging, internal organs were not affected. Sequential treatment with lomustine and doxorubicin failed to prevent progression of the cutaneous lesions, and the dog died 3 months after initial diagnosis. At necropsy, a focus of neoplastic cells was present in one lymph node, but except for skin other organs were not involved. The clinical presentation of histiocytic sarcoma may be unusual, and neoplastic cells may lack overt features of malignancy on cytologic and histopathologic examination. In some instances, immunophenotyping is required to differentiate histiocytic sarcoma from other histiocytic disorders.
authors: Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA. czm0010@auburn.edu
authors: Cinzia
authors: C
authors: Mastrorilli
authors: Elizabeth A
authors: EA
authors: Spangler
authors: Peter W
authors: PW
authors: Christopherson
authors: Oceane A
authors: OA
authors: Aubry
authors: Joseph C
authors: JC
authors: Newton
authors: Annette N
authors: AN
authors: Smith
authors: Robert A
authors: RA
authors: Kennis
authors: Jaime L
authors: JL
authors: Weismann
authors: Peter F
authors: PF
authors: Moore
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D015703:Antigens, CD / Q000276:immunology / Q000378:metabolism*; D000970:Antineoplastic Agents / Q000627:therapeutic use; D044963:Biopsy, Fine-Needle / Q000662:veterinary; D002506:Cephalexin / Q000627:therapeutic use; D003713:Dendritic Cells / Q000276:immunology / Q000473:pathology; D004283:Dog Diseases / Q000188:drug therapy / Q000276:immunology / Q000473:pathology*; D004285:Dogs; D004317:Doxorubicin / Q000627:therapeutic use; D017809:Fatal Outcome; D006644:Histiocytes / Q000276:immunology / Q000473:pathology; D054747:Histiocytic Sarcoma / Q000188:drug therapy / Q000276:immunology / Q000473:pathology / Q000662:veterinary*; D015614:Histiocytosis / Q000662:veterinary; D016130:Immunophenotyping / Q000662:veterinary*; D008130:Lomustine / Q000627:therapeutic use; D008297:Male; D011241:Prednisone / Q000627:therapeutic use; D012867:Skin / Q000276:immunology / Q000473:pathology; D012878:Skin Neoplasms / Q000188:drug therapy / Q000276:immunology / Q000473:pathology / Q000662:veterinary*
chemical_list: D000900:Anti-Bacterial Agents; D015703:Antigens, CD; D000970:Antineoplastic Agents; D008130:Lomustine; D004317:Doxorubicin; D002506:Cephalexin; D011241:Prednisone