Systemic histiocytosis: Dogs may not show signs
May 01, 2003
Signalment Canine, Bernese Mountain dog, 9 years old, female spayed, 70 lbs.
Physical examination The findings include rectal temperature 101.6° F, heart rate 150/min, respiratory rate 45/min, pale mucous membranes, normal capillary refill time, normal heart sounds and coarse lung sounds. The dog has had weight loss of 9 lbs. in the past two months and now has a palpable abdominal mass.
Ultrasound examination: Thorough abdominal ultrasonography was performed. The dog was positioned in dorsal recumbency for the ultrasonography.
The gall bladder is mildly distended, and its walls are not thickened or hyperechoic. The gall bladder does contain some sludge material. The spleen is irregularly enlarged and shows mixed echogenicity in its parenchyma.
Case management: In this case, intra-abdominal neoplasia is the clinical diagnosis. Beware of malignant histiocytosis of Bernese Mountain dogs. At this point, an exploratory laparotomy would be warranted to confirm the presence of neoplasia, excise the abnormal spleen, inspect the abdominal cavity for potential metastatic disease and collect appropriate biopsies for histopathologic examination. Therapy, thereafter, would depend on the findings from the exploratory laparotomy and histopathologic examination.
Familial disease of Bernese mountain dogs is inherited by polygenic mode; heritability is 0.298; and accounts for up to 25 percent of all tumors in this breed. Dogs with systemic histiocytosis may not have any signs of systemic illness.
Dogs that do may show cutaneous masses - multiple, nodular, well-circumscribed and often ulcerated, crusted or alopecic - of the muzzle, nasal planum, eyelids, flank and scrotum; moderate to severe peripheral lymphadenomegaly; ocular manifestations - conjunctivitis, chemosis, scleritis, episcleritis, episcleral nodules, corneal edema, anterior and posterior uveitis, retinal detachment, glaucoma and exophthalmos; abnormal respiratory sounds and/or nasal mucosa infiltration; and organomegaly.