Clinical Vignette

Abstract

A known age), weighing 4.4 kg was presented for lethargy and decreased appetite of approximately 2 weeks' duration. The referring veterinarian had diagnosed anemia [packed cell volume (PCV) = 17.8%] and treated the cat with tetracycline (250 mg PO bid for 10 days) and prednisone (2.5 mg PO sid for 7 days). The cat was referred to the North Carolina State University Veterinary Teaching Hospital after the PCV continued to decrease and icterus became clinically apparent.On physical examination, the cat was pale, ictenc, and severely depressed. He had a rectal temperature of 38.3"C, a heart rate of 144 beats per minute, and a respiratory rate of 60 per minute. An S4 gallop and a III/VI systolic murmur over the area of the mitral valve were auscultated. Hepatomegaly and splenomegaly were noted on abdominal palpation.Results of a CBC revealed Coombs'-positive anemia (hematocrit = 7.470, reference range = 24.0% to 45.0%; erythrocyte count = 1.10 X 106/gL, reference range = 5.00 to 10.0 X 106/pL; hemoglobin = 2.2 g/dL, reference range = 8.0 to 15.0 g/dL), without evidence of regeneration (uncorrected aggregate reticulocytes = 3.5%. punctate reticulocytes = 2.5%, and 1 1 nucleated red blood cells/l00 white blood cells), macrocytosis (MCV = 67.3 fL, reference range = 39.0 to 55.0 fL), thrombocytopenia (83.000/gL, reference range = 300,000 to SOO,OOO/pL), and mild anisocytosis and polychromasia. Abnormal white blood cells were not seen on peripheral blood smears. Serum biochemical abnormalities included hypoproteinemia (3.8 g/dL, reference range = 6.3 to 8.7 g/dL), hypoalbuminemia (2.1 g/dL, reference range = 2.7 to 4.6 g/dL), hyperbilirubinemia (2.9 mg/dL, reference range = 0.15 to 0.20 mg/dL), and hypokalemia (3.2 mEq/L, reference range = 4.0 to 4.8 mEq/L). No abnormalities were noted on the urinalysis or coagulation profile. Abdominal radiographs revealed moderate hepatosplenomegaly, with mild right renomegaly.Initial treatment included a transfusion of 60 m L of fresh whole blood and IV fluids (lactated Ringers solution with 20 mEq KCI/L) at a dose of 55 rnL/kg/day. Prednisone ( 5 mg PO bid) also was administered to treat suspected autoimmune hemolytic anemia. On day 2 of hospitalization, the PCV had increased to 15%, and the cat was more alert and began to eat, although his temperature had increased to 39.7". Cephalexin (90 mg IV tid) was added to the treatment regimen because of the possibility of infection. Serology results for feline leukemia and feline immunodeficiency virus were negative. A bone marrow aspirate and core biopsy were collected from the humerus. An imprint from the biopsy revealed a dense proliferation of moderately differentiated histiocytic cells with pleomorphic nuclei and indistinct cell borders ( Fig I); erythrophagocytosis was also a prominent feature. Cytological features of the liver, obtained by percutaneous aspirate, were similar to those of the bone marrow, including numcrous histiocytic cells with leukophagocytosis and erythrophagocytosis. Bone marrow smears stained positive for nonspeci...

Histiocytic sarcoma of macrophage origin in a cat: case report with a literature review of feline histiocytic malignancies and comparison with canine hemophagocytic histiocytic sarcoma

“…The cause of anemia in cats with MH is likely multifactorial and includes destruction by neoplastic histiocytes, decreased production owing to marrow infiltration, and perhaps a component of immune‐mediated hemolysis 8 . A Coombs' test was positive in 1 of 3 cats with MH 5,6,8 . Destruction by neoplastic histiocytes is likely the primary cause of hemolytic anemia in dogs with hemophagocytic HS and was thought to be a major factor in this patient.…”

“…MH and HS are uncommon diagnoses in cats. Nine case reports encompassing 11 cats were found in the literature 4–12 . The term MH was used in 7 cases, in which the malignancy was disseminated widely.…”

“…Because there was no clinical evidence of hemorrhage, the erythroid hyperplasia observed in the marrow biopsy was attributed to RBC destruction. Six of 7 cats with disseminated MH had moderate to severe anemia with normal (1 cat) to mildly increased (5 cats) bilirubin concentrations 5–8 . Only one of these cats had evidence of mild regeneration 8 ; the rest were poorly regenerative to nonregenerative 5–7 .…”

Dynamic tracheal collapse associated with disseminated histiocytic sarcoma in a cat

“…HS and malignant histiocytosis are rare in cats. There are eight previously reported cases of feline malignant histiocytosis (Gafner and Bestetti 1988, Court and others 1993, Freeman and others 1995, Walton and others 1997, Fritz and others 1999, Kraje and others 2001) and two reports of HS (Tanimoto and others 1988, Smoliga and others 2005). All were adult domestic shorthair cats, with an age range of 1 to 13 years.…”

“…The most common presenting signs were weight loss, lethargy and anorexia, although pyrexia, tachycardia, dyspnoea, neurological dysfunction, body cavity effusions, lymphadenopathy and hepatosplenomegaly have also been reported. Clinicopathological abnormalities in the affected cats include anaemia, sometimes Coombs’ positive (Freeman and others 1995), prolongation of clotting times, hypoproteinaemia, hyperbilirubinaemia and mild hyperglycaemia (Court and others 1993, Freeman and others 1995, Kraje and others 2001). One cat was positive for feline leukaemia virus (FeLV).…”