Abdominal Spindle Cell Sarcoma of Probable Myofibroblastic Origin in a Horse

Abstract

An 18-year-old gelding Thoroughbred was referred to Virginia-Maryland Regional College of Veterinary Medicine for evaluation of anorexia, pyrexia, chronic weight loss, and a distended abdomen. Three years previously, this horse was diagnosed with acute septic hepatocholangitis based on physical, bacteriologic, biochemical, and histopathologic findings. Streptococcus viridans was isolated from the liver biopsy samples. Treatment included intravenous fluids, B vitamins, and antibiotics. The horse recovered and had normal blood chemistry and complete blood counts within 5 months of this episode. After recovery, the horse developed intermittent dermal photosensitization involving the lightly pigmented skin of the distal hind limbs.Current physical examination findings included mild depression, lethargy, patchy alopecia and scaling, abdominal distention, generalized muscle atrophy, and poor body condition. There were bilaterally symmetrical 10 ϫ 5 ϫ 1-cm raised swellings in the subcutaneous tissue of the prepuce. Serum biochemical analysis revealed hyperproteinemia (8.8 g/dl). The horse had a leukocytosis (20.1 ϫ 10 3 cells/l) characterized by mature neutrophilia (17.69 ϫ 10 3 cells/l). Results of serum electrophoresis were consistent with chronic inflammation. All other blood parameters were considered normal. Rectal palpation identified a large nodular mass in the caudal abdomen that was confirmed by transrectal and transabdominal ultrasound examination. No distinct organ involvement was identified, and the liver appeared normal. Abdominocentesis yielded a voluminous yellow/orange turbid fluid with an elevated protein level (4.7 g/dl) but a normal total nucleated cell count (300 cells/l). Neutrophils and small lymphocytes were identified on cytologic preparations. Ultrasound examination of the parapreputial swellings demonstrated subcutaneous multiloculated masses. Cytologic examination of fluid obtained by fine-needle aspiration from these masses revealed a monomorphic population of small lymphocytes and occasional erythrophagocytic macrophages.Because of the rapid and severe deterioration of the patient and a high suspicion of abdominal neoplasia, the horse was euthanized and a postmortem examination was performed. Necropsy examination revealed significant muscle atrophy and loss of body fat stores, with grossly observable prominent bony processes and ribs. The abdominal cavity contained approximately 250 ml of clear yellow fluid in as- Received for publication June 11, 1998. sociation with a multiloculated, encapsulated, cystic 81.82-kg mass within the intestinal mesentery (Fig. 1). The mass was cavitated and contained 5-7 liters of red fluid admixed with gelatinous tan material and blood clots. The capsule was thick, firm, and white and composed of variable amounts of fibrous connective tissue, which surrounded and encapsulated many of the enlarged, swollen mesenteric lymph nodes. Numerous fibrous adhesions extended from the capsular surface of the mass to the serosal surface of loops of both the small and l...

Diagnostic Features of Feline Restrictive Orbital Myofibroblastic Sarcoma

“…8 A recent report described a retrobulbar inflammatory myofibroblastic tumor in a dog. 16 Isolated reports of similar proliferative and fibrosing lesions in anatomic sites remote from the orbit have been reported in the horse, 4,24,28 goat, 27 cat, 15,23 macaques, 11 and dogs. 3,6,10,16,29 A study by Qiu et al 25 compared inflammatory myofibroblastic tumors and low-grade myofibroblastic sarcoma in humans, concluding that the two are distinct clinicopathologic entities with key genetic and histologic differences.…”

Myofibroblastoma of the Neck in a Heifer.

“…Myofibroblasts may be contained in various fibroblastic tumors [3], and tumors consisting predominantly or most entirely of myofibroblasts exist in human beings [5,13]. A vulval myofibroblastoma has been reported in a cow [1], and sarcomas of myofibroblastic origin have been described in two cats [2,6] and a horse [9]. This paper reports a myofibroblastoma in a heifer, whose myofibroblastic nature was confirmed immunohistochemically and ultrastructurally.…”

“…The present tumor, by contrast, showed intense PCNA positivity in most neoplastic cells, and was locally aggressive, seemingly`having a biological behavior intermediate between the benign fibroblastic tumors and fibrosarcoma. Malignant tumors of myofibroblasts are rare in humans [3,12] and animals, but sarcomas of myofibroblasts or probable myofibroblastic origin have been recorded in some animal species [2,6,9].…”

Internal neoplasia in the horse with special regard to the cytology of body cavity fluid

“…In der Literatur gibt es eine Vielzahl von Einzelfalldarstellungen von Tumoren mit Beteiligung abdominaler oder thorakaler Organe, wie metastasierendes Ovarialkarzinom (Gift et al 1992), multiples Dysgerminom (Chandra et al 1998), Bronchialkarzinom (Schultze et al 1988, Anderson et al 1992, Gehlen et al 2006, Granularzelltumor der Lunge , Gehlen et al 2006, Hepatoblastom (Prater et al 1989), Gallengangskarzinom (East und Savage 1998), mediastinales Plattenepithelkarzinom (Hovda et al 1990), Nierenzellkarzinom (Ocarino et al 2006), Karzinom des Übergang-epithels der Harnblase (Patterson-Kane et al 2000), Leiomyosarkom (Rossdale et al 2004), Sarkom (Früh et al 2004), Fibrosarkom (Newman et al 1999), Chondrosarkom (Mair und Brown 1993), Phäochromozytom (Yovich et al 1984), Tumore des Urogenitaltrakts und ihre Metastasen (Köllmann et al 2006), die nicht Gegenstand dieser Veröffentlichung sind.…”