An Unusual Case of Giant Cell Tumor of Soft Parts in an American Warmblood Horse

• Published in: Open veterinary journal Vol. 9; no. 1; pp. 44 - 48
• Main Authors: Leonardi , Leonardo, Zimmerman , Kurt, Crisman , Mark, Saunders , Geoff, Almy , Frederic
• Format: Journal Article
• Language: English
• Published: Tarabulus - Libya Faculty of Veterinary Medicine, University of Tripoli 01.01.2019; Faculty of Veterinary Medicine; Tripoli University
• Subjects: ANIMAL DISEASES; Animals; Case Report; Cytology; Equine; Giant Cell Tumor of Soft Parts; Giant Cell Tumors - diagnosis; Giant Cell Tumors - pathology; Giant Cell Tumors - veterinary; HISTIOCYTOMAS; HISTOPATHOLOGY; Horse Diseases - diagnosis; Horse Diseases - pathology; HORSES; Male; NEOPLASMS; Soft Tissue Neoplasms - diagnosis; Soft Tissue Neoplasms - pathology; Soft Tissue Neoplasms - veterinary; VETERINARY MEDICINE; أمراض الحيوان; أورام الخلايا النسيجية; الأورام; الخيول; الطب البيطري; علم أمراض الأنسجة; Equine; Giant cell tumor of soft parts; Histopathology; Cytology
• DOI: 10.4314/ovj.v9i1.8
• ISSN: 2226-4485; 2218-6050

Fine needle aspiration and tissue biopsy samples were taken from a subcutaneous mass in the cranial stifle region of a 10-yr-old horse. Key cytologic features included numerous mildly to moderately pleomorphic histiocytic cells admixed with mononuclear inflammatory cells, occasional fibroblasts, multinucleated cells, and hemosiderin-laden macrophages. Based on these features, cytologic differentials included granulomatous inflammation with reactive fibroplasia, histiocytic sarcoma, giant cell tumor of soft parts (GCTSPs), and giant cell tumor of bone. The tissue biopsy supported a diagnosis of superficial GCTSPs. This neoplasm is of controversial origin but generally considered to be a soft tissue sarcoma and classified in the World Health Organization classification of tumors under fibrous histiocytic tumors as a giant cell tumor of soft tissue with low risk of malignancy. When found in the subcutis, this neoplasm rarely metastasizes in the horse and has a low rate of local reoccurrence. In this case, there was no local recurrence of the tumor after 6 mo, after which the horse was lost to follow-up.